Category: ADHD

HSDs/hEDS, autism and ADHD relationship

When looking at the literature on hypermobility spectrum disorders and hypermobile Ehlers-Danlos syndrome, it becomes clear that there is a relationship between those conditions and a patient also presenting with comorbid autism spectrum disorder and/or ADHD. This also extends out to the wider spectrum of Ehlers-Danlos Syndromes of other types, with it appearing to be a commonality across the syndrome family. Therefore, it can be considered within the range of “normal” for those conditions to be presented with that comorbidity.

Some of the literature showing this link includes, but is not limited to: 

  • “Lack of attention is now considered a common feature in children with gJHM and JHS/EDS-HT, as documented by the high rate of attention deficit (and hyperactivity) disorder in these conditions.”
    Neurodevelopmental attributes of joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type: Update and perspectives – Ghilbellini, Brancati & Castori (2015) – https://doi.org/10.1002/ajmg.c.31424      
  • “Psychiatric conditions in which there is some evidence of an association with JH/HDCT are anxiety disorders, depression, schizophrenia, neurodevelopmental disorders (autism, attention deficit/hyperactivity disorder, and developmental coordination disorder), eating disorders, personality disorders and substance use/misuse.”
    Joint hypermobility and the heritable disorders of connective tissue: clinical and empirical evidence of links with psychiatry – Baeza-Velasco, Pailhez, Bulbena & Baghdadli (2015) – https://doi.org/10.1016/j.genhosppsych.2014.10.002 
  • “Children with ASDs had significantly greater joint mobility (p < .002), more gait abnormalities (p < .0001), and on average walked 1.6 months later than their non-autistic peers.”
    Abnormalities of joint mobility and gait in children with autism spectrum disorders – Shetreat-Klein, Shinnar & Rapin (2012) – https://doi.org/10.1016/j.braindev.2012.02.005 
  • “EDS was associated with ASD: risk ratio (RR) 7.4, 95 % confidence interval (95 % CI) 5.2-10.7; bipolar disorder: RR 2.7, CI 1.5-4.7; ADHD: RR 5.6, CI 4.2-7.4; depression: RR 3.4, 95 % CI 2.9-4.1; and attempted suicide: RR 2.1, 95 % CI 1.7-2.7, but not with suicide or schizophrenia. EDS siblings were at increased risk of ADHD: RR 2.1, 95 % CI 1.4-3.3; depression: RR 1.5, 95 % CI 1.1-1.8; and suicide attempt: RR 1.8, 95 % CI 1.4-2.3. Similar results were observed for individuals with hypermobility syndrome and their siblings.” 
    Nationwide population-based cohort study of psychiatric disorders in individuals with Ehlers-Danlos syndrome or hypermobility syndrome and their siblings – Cederlof, Larsson, Lichtenstein, Almqvist, Serlachius & Ludvigsson (2016) – https://doi.org/10.1186/s12888-016-0922-6
  • “This article reviews the pertinent literature concerning neurodevelopmental conditions for which there is some evidence of an association with JHM/HSD/EDS. These include hyperactivity and attention deficit, learning, communication, and motor problems including tic disorders such as Tourette syndrome and autism spectrum disorders.” 
    Neurodevelopmental atypisms in the context of joint hypermobility, hypermobility spectrum disorders, and Ehlers–Danlos syndromes – Baeza-Velasco (2021) – https://doi.org/10.1002/ajmg.c.31946
  • “ADHD was the third more common neurodevelopmental disorder in our sample as it occurred in 13% of the cases, compared to 5% in the pediatric population (APA, 2013). Our observation confirms the slight rate increase (7%) of ADHD in EDS adults reported by Hershenfeld et al. (2016). A recent nationwide population-based study in Sweden demonstrated an increased risk of ADHD in people with EDS or JHS, and their siblings (risk ratio 5.6 and 2.1, respectively) (Cederlof et al., 2016).” 
    Exploring relationships between joint hypermobility and neurodevelopment in children (4–13 years) with hereditary connective tissue disorders and developmental coordination disorder – Piedimonte, Penge, Morlino, Sperduti, Terzani, Giannini, Colombi, Grammatico, Cardona & Castori (2018) – https://doi.org/10.1002/ajmg.b.32646
    Referencing: 
    • Psychiatric disorders in Ehlers-Danlos syndrome are frequent, diverse and strongly associated with pain – Hershenfeld, Wasim, McNiven, Parikh, Majewski, Faghfoury & So (2016) – https://doi.org/10.1007/s00296-015-3375-1
    • Nationwide population-based cohort study of psychiatric disorders in individuals with Ehlers-Danlos syndrome or hypermobility syndrome and their siblings – Cederlof, Larsson, Lichtenstein, Almqvist, Serlachius & Ludvigsson (2016) – https://doi.org/10.1186/s12888-016-0922-6
  • “Considerable interest has arisen concerning the relationship between hereditary connective tissue disorders such as the Ehlers-Danlos syndromes (EDS)/hypermobility spectrum disorders (HSD) and autism, both in terms of their comorbidity as well as co-occurrence within the same families. […] Together, these data highlight the potential relatedness of these two conditions and suggest that EDS/HSD may represent a subtype of autism.” 
    The Relationship between Autism and Ehlers-Danlos Syndromes/Hypermobility Spectrum Disorders – Casanova, Baeza-Velasco, Buchanan & Casanova (2020) – https://doi.org/10.3390%2Fjpm10040260
  • “All EDS cases could be classified as hEDS. Of the entire study cohort, 16% had a verified ADHD diagnosis and a further 7% were undergoing ADHD diagnostic investigation. Significantly more children with hEDS had ADHD compared to children with HSD (p=0.02). In the age group 15– 16 years, 35% of those with hEDS had ADHD and, among those aged 17– 18 years, ADHD was present in 46%. Children with coexisting ADHD showed a significantly higher proportion of associated symptoms such as fatigue, sleep-problems, and urinary tract problems. ASD had been verified in 6% of the children. Of those with ASD, 92% had sleep problems. This study shows a strong association between HSD or hEDS and ADHD or ASD. Therefore, children with HSD or hEDS may need to be routinely screened for neuropsychiatric symptoms.” 
    Prevalence of ADHD and Autism Spectrum Disorder in Children with Hypermobility Spectrum Disorders or Hypermobile Ehlers-Danlos Syndrome: A Retrospective Study – Kindgren, Quinones & Knez (2020) – https://doi.org/10.2147/NDT.S290494
  • “The neurodivergent group manifested elevated prevalence of hypermobility (51%) compared to the general population rate of 20% and a comparison population (17.5%). Using a more stringent age-specific cut-off, in the neurodivergent group this prevalence was 28.4%, more than double than the comparison group (12.5%).” 
    Joint Hypermobility Links Neurodivergence to Dysautonomia and Pain – Csecs, Iodice, Rae, Brooke, Simmons, Quadt, Savage, Dowell, Prowse, Themelis, Mathias, Critchley & Eccles (2022) – https://doi.org/10.3389/fpsyt.2021.786916
  • “ASD and HRDs, specially hEDS, are conditions with a strong genetic component, a polymorphic clinical presentation, appearing both in infancy, and sharing several phenotypical features. Although existing data does not allow to ascertain increase prevalence of ASD in HRDs, as well as shared underlying patho-mechanisms between both conditions, there is increasing evidence suggesting that these co-occur more often than expected by chance.” 
    Autism, Joint Hypermobility-Related Disorders and Pain – Baeza-Velasco, Cohen, Hamonet, Vlamynck, Diaz, Cravero, Cappe & Guinchat (2018) – https://doi.org/10.3389/fpsyt.2018.00656
  • “We demonstrate for the first time that rates of hypermobility and symptoms of autonomic dysfunction are particularly high in adults with neurodevelopmental diagnoses.” 
    Joint Hypermobility and Autonomic Hyperactivity: Relevance to Neurodevelopmental Disorders – Eccles, Iodice, Dowell, Owens, Hughes, Skipper, Lycette, Humphries, Harrison, Mathias & Critchley (2014) – http://dx.doi.org/10.1136/jnnp-2014-308883.9
  • “We speculate that associations exist between connective tissue diseases and autistic disorders, and that connective tissue abnormalities may contribute to autistic symptoms.” 
    High-functioning autistic disorder with Ehlers-Danlos syndrome – Takei, Mera, Sato & Haraoka (2011) – https://doi.org/10.1111/j.1440-1819.2011.02262.x
  • “The results of this study support that joint hypermobility may be associated with ADHD, and this condition should be taken into consideration in assessing the complaints of patients with ADHD-related musculoskeletal symptoms.” 
    Benign Joint Hypermobility Syndrome in Patients with Attention Deficit/Hyperactivity Disorders – Koldas Dogan, Taner & Evcik (2011) – https://doi.org/10.5152/tjr.2011.029
  • “These data suggest that EDS/HSD and autism share aspects of immune/autonomic/endocrine dysregulation, pain, and some tissue fragility, which is typically more severe in the former. This overlap, as well as documented comorbidity, suggests some forms of autism may be hereditary connective tissue disorders (HCTD).” 
    Immune, Autonomic, and Endocrine Dysregulation in Autism and Ehlers-Danlos Syndrome/Hypermobility Spectrum Disorders Versus Unaffected Controls – Casanova, Sharp, Edelson, Kelly, Sokhadze & Casanova (2019) – https://doi.org/10.1101/670661
  • “GJH was assessed by physical examination following the Beighton scoring system (BSS). Furthermore, musculoskeletal symptoms and skin abnormalities were queried to create a proxy for symptomatic GJH (e.g., Hypermobility spectrum disorders and Ehlers-Danlos syndrome) to differentiate this from non-specified GJH defined by BSS only  Logistic regression examined the influence of ADHD and candidate covariates (age, sex, ethnicity) on GJH and symptomatic GJH, respectively. ADHD was significantly associated with GJH, as defined by the BSS, with adjusted odds ratios of 4.7 (95% confidence interval [CI] 3.0–7.2, p < .005). Likewise, ADHD was significantly associated with symptomatic GJH, as defined by the BSS and additional symptoms, with adjusted odds ratios of 6.9 (CI 95% 4.1–11.9, p < .005). Our results suggest that GJH may represent a marker for an underlying systemic disorder involving both connective tissue and the central nervous system. GJH with additional musculoskeletal symptoms and/or skin abnormalities has a considerable stronger link to adult ADHD than non-specified GJH has, and may need awareness in ADHD management. Future studies should investigate the mechanisms behind this association and how comorbid GJH affects ADHD outcome.” 
    Association between adult attention-deficit hyperactivity disorder and generalised joint hypermobility: A cross-sectional case control comparison – Glans, Thelin, Humble, Elwin & Bejerot (2021) – https://doi.org/10.1016/j.jpsychires.2021.07.006
  • “Joint laxity was discovered in 74.4% of children with attention deficit hyperactivity disorder and in 12.8% of healthy controls. The prevalence of benign joint hypermobility syndrome was high in children with attention deficit hyperactivity disorder, which shows a new basis for further studies.”
    Evaluation of the Prevalence of Joint Laxity in Children with Attention Deficit/Hyperactivity Disorder – Shiari, Saeidifard & Zahed (2013) – https://doi.org/10.5455/apr. 032420131219 
  • “The significant findings in the SCT scale and observed trends in other attention-related scales indicate that larger future studies are needed to further elucidate the relationship between EDS-HT and attention problems. An association between EDS-HT and ADHD may influence clinical management of patients with both disorders.” 
    Pilot Study of Attention Deficit Hyperactivity Disorder-related Behaviors in a Pediatric Ehlers-Danlos Syndrome-Hypermobility type Population (Thesis) – Reinert (2015) – https://etd.ohiolink.edu/apexprod/rws_etd/send_file/send?accession=ucin1427796903&disposition=inline 
  • “While this study cannot address rates of ASD and GJH co-occurrence because of the way in which respondents were recruited, the comorbidity itself reinforces etiological links between autism and connective tissue disorders. Both cytokines and hormones play recognized roles in neurogenesis, neuritogenesis, synaptogenesis, and ongoing plasticity. In addition, some researchers have proposed that autoantibodies to brain-specific proteins may also disrupt neurodevelopment, leading to increased autism risk. Finally, endocrine disruption, either via endogenous or exogenous effectors, is likewise a growing area of research into autism’s etiology. All of these topics highlight the crosstalk between the immune and endocrine systems and strengthen their combined links to ASD.” 
    A Cohort Study Comparing Women with Autism Spectrum Disorder with and without Generalized Joint Hypermobility – Casanova, Sharp, Edelson, Kelly & Casanova (2018) – https://doi.org/10.3390/bs8030035
  • “Logistic regression models adjusting for covariates (age, sex, ethnicity) revealed a significant relationship between ASD and GJH and between ASD and symptomatic GJH, with adjusted odds ratios of 3.1 (95% CI: 1.9, 5.2; p < 0.001) and 4.9 (95% CI: 2.6, 9.0; p < 0.001), respectively. However, the high prevalence of comorbid ADHD in the study sample reduces the generalizability of the results among individuals with ASD without comorbid ADHD. Possibly, an additional ADHD phenotype is the primary driver of the association between ASD and GJH. Furthermore, GJH with additional self-reported symptoms, suggestive of HSD/hEDS, showed a stronger association with ASD than did non-specified GJH, indicating that symptomatic GJH plays a greater role in the relationship than non-specified GJH does.” 
    The Relationship Between Generalised Joint Hypermobility and Autism Spectrum Disorder in Adults: A Large, Cross-Sectional, Case Control Comparison – Glans, Thelin, Humble, Elwin & Bejerot (2022) – https://doi.org/10.3389/fpsyt.2021.803334
  • “The extent of hypermobility among children with Autism Spectrum Disorder was 60%, that is, 70 out of 117 children had hypermobility. Our results also suggested that the age, height, weight, and BMI of the child had a moderate negative correlation with hypermobility.” 
    Hypermobility among children with autism spectrum disorders and its correlation with anthropometric characteristics – Shanker Tedla, Asiri, Saeed Alshahrani & Gular (2021) – https://doi.org/10.47391/jpma.436 

This overlapping relationship is to note as it adds additional risk factors when managing those with these co-occurring disabilities, most notably in the field of mental health. HSD and hEDS are linked to mental health conditions, as are autism and ADHD, meaning that when there is an intersection of these conditions within one patient, the risk of mental health issues increases.

Autism and ADHD – A Common Co-Occurring Presentation

How common is a co-diagnosis of autism and ADHD? Let’s take a look at the available literature on the topic

Despite a dual diagnosis of ADHD and any autism spectrum disorder being unable to be diagnosed before the publication of the DSM V in 2013, there is evidence in scientific literature that highlights that the presentation of traits that met the diagnostic threshold for both conditions that pre-dates the DSM V changes.

Since the addition of the ability to co-diagnose these conditions was added in 2013, the high rates of formal recognition of their co-occurrence has also been recognised in academic literature.

Studies show that those with dual autism/ADHD presentation face more challenges and have a lower quality of life and lesser outcomes than their individual diagnosis peers, and one of the reasons why can be the misinformation and misconception that lingers that these conditions cannot co-occur in an individual.

For the autistic, ADHD and dual autistic/ADHD communities, it is important that parents, caregivers, practitioners, and the communities themselves recognise the co-occurence rate in order to ensure that adequate support is provided for both conditions when they present in an individual and that the approach is adjusted and optimised in order to ensure the best opportunities and outcomes.

Some of the evidence that highlights this includes, but is not limited to:

  • “Of 83 children, 78% fulfilled Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for ADHD and exceeded the 93rd percentile norm for the ADHD RS. Hyperactivity-impulsivity scores were significantly greater in individuals with autism than those with other ASDs. DSM-IV ADHD diagnosis was represented equally in individuals with and without ADHD as their chief complaints. ADHD RS hyperactivity-impulsivity and total scores were negatively correlated with age.” Attention-deficit hyperactivity disorder symptoms in a clinic sample of children and adolescents with pervasive developmental disorders – Lee & Ousley (2006) – http://dx.doi.org/10.1089/cap.2006.16.737

  • “The Kiddie Schedule for Affective Disorders and Schizophrenia was modified for use in children and adolescents with autism by developing additional screening questions and coding options that reflect the presentation of psychiatric disorders in autism spectrum disorders. The modified instrument, the Autism Comorbidity Interview-Present and Lifetime Version (ACI-PL), was piloted and frequently diagnosed disorders, depression, ADHD, and OCD, were tested for reliability and validity. The ACI-PL provides reliable DSM diagnoses that are valid based on clinical psychiatric diagnosis and treatment history. The sample demonstrated a high prevalence of specific phobia, obsessive compulsive disorder, and ADHD. The rates of psychiatric disorder in autism are high and are associated with functional impairment.”
    • Comorbid psychiatric disorders in children with autism: interview development and rates of disorders – Leyfer, Folstein, Bacalman, Davis, Dinh, Morgan, Tager-Flusberg & Lainhart (2006) – https://doi.org/10.1007/s10803-006-0123-0

  • “Nine hundred forty-six twins identified by Missouri birth records were assigned to DSM-IV ADHD diagnoses and seven population-derived ADHD subtypes defined through latent class analysis of DSM-IV ADHD symptoms. The Social Responsiveness Scale (SRS) was used as a quantitative measure of autistic traits. […] Mean SRS scores for DSM-IV predominantly inattentive subtype and combined subtype ADHD groups were significantly higher than for subjects without DSM-IV ADHD (p <.001, both comparisons). Five of the population-derived ADHD subtypes (talkative-impulsive, mild and severe inattentive, mild and severe combined) had significantly higher mean SRS scores compared to the latent class subtype with few ADHD symptoms (p <.001, all comparisons). DSM-IV combined subtype and the population-derived severe combined subtype had the highest mean total SRS scores and the highest mean scores for each of the three autism symptom domains, with a substantial proportion of individuals scoring in the clinically significant range. […] This study provides population-based evidence for clinically significant elevations of autistic traits in children meeting diagnostic criteria for ADHD. These results have implications for the design and interpretation of studies of both disorders.”

  • “Seventy percent of participants had at least one comorbid disorder and 41% had two or more. The most common diagnoses were social anxiety disorder (29.2%, 95% confidence interval [CI)] 13.2-45.1), attention-deficit/hyperactivity disorder (28.2%, 95% CI 13.3-43.0), and oppositional defiant disorder (28.1%, 95% CI 13.9-42.2).”
    • Psychiatric disorders in children with autism spectrum disorders: prevalence, comorbidity, and associated factors in a population-derived sample – Simonoff, Pickles, Charman, Chandler, Loucas & Baird (2008) – https://doi.org/10.1097/chi.0b013e318179964f

  • “In some cases the inadequate social behavior of children with ADHD may be phenomenologically and etiologically related to pervasive developmental disorders (PDD). However, the causes and consequences of PDD symptoms in ADHD are understudied.”

  • “Recent estimates suggest that 31% of children with autism spectrum disorders (ASD) meet diagnostic criteria for attention deficit/hyperactivity disorder (ADHD), and another 24% of children with ASD exhibit subthreshold clinical ADHD symptoms. Presence of ADHD symptoms in the context of ASD could have a variety of effects on cognition, autistic traits, and adaptive/maladaptive behaviors including: exacerbating core ASD impairments; adding unique impairments specific to ADHD; producing new problems unreported in ASD or ADHD; having no clear impact; or producing some combination of these scenarios.”
    • Attention deficit/hyperactivity disorder symptoms moderate cognition and behavior in children with autism spectrum disorders – Yerys, Wallace, Sokoloff, Shook, James & Kenworthy (2009) – https://doi.org/10.1002/aur.103

  • “Of the sample, 53% fulfill DSM-IV criteria for ADHD. The comparison of the ASD+ and the ASD- samples reveals differences in age and IQ. Correlations of ADHD and PDD show significant results for symptoms of hyperactivity with impairment in communication and for inattention with stereotyped behavior. Item profiles of ADHD symptoms in the ASD+ sample are similar to those in a pure ADHD sample.”
    • Attention Deficit/Hyperactivity Disorder in Children and Adolescents With Autism Spectrum Disorder: Symptom or Syndrome? – Sinzig, Walter & Doepfner (2009) – https://doi.org/10.1177/1087054708326261

  • “Attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are both highly heritable neurodevelopmental disorders. Evidence indicates both disorders co-occur with a high frequency, in 20–50% of children with ADHD meeting criteria for ASD and in 30-80% of ASD children meeting criteria for ADHD. This review will provide an overview on all available studies [family based, twin, candidate gene, linkage, and genome wide association (GWA) studies] shedding light on the role of shared genetic underpinnings of ADHD and ASD. It is concluded that family and twin studies do provide support for the hypothesis that ADHD and ASD originate from partly similar familial/genetic factors.”

  • “Results confirm the presence of a subgroup of children with ADHD and elevated ratings of core ASD traits (ADHD+) not accounted for by ADHD or behavioral symptoms. Further, analyses revealed greater oppositional behaviors, but not greater ADHD severity or anxiety, in the ADHD+ subgroup compared to those with ADHD only. These results highlight the importance of specifically examining autistic traits in children with ADHD for better characterization in studies of the underlying physiopathology and treatment.“
    • Examining Autistic Traits in Children with ADHD: Does the Autism Spectrum Extend to ADHD? – Grzadzinski, Martino, Brady, Mairena, O’Neale, Petkova, Lord & Castellanos (2011) – https://doi.org/10.1007/s10803-010-1135-3

  • “This review has demonstrated that the differences in neuropsychological and clinical profiles of both children with autism and those with ADHD are fairly evident when the disorders are considered in their pure form. The manifestations of these disorders in their comorbid form, however, are less clear, due to a lack of research in this area stemming from the prohibition of comorbid diagnoses by the major international classification systems. Recent clinical opinion, research practice and theoretical models seem to suggest that comorbidity between disorders is a real, relevant, and frequent occurrence.”

  • “In this study, a substantial proportion of the children with ADHD presented with elevated parent ratings of autistic traits (ADHD+). The proportion varied from about one-third, when using either the SRS or the CCC-2, to about one-fifth when both measures were combined to identify ADHD+.”
    • Examining autistic traits in children with ADHD: Does the Autism Spectrum Extend to ADHD? – Grazadizinski, Martino, Brady, Angeles Mairena, O’Neale, Petkova, Lord & Casellanos (2011) – https://doi.org/10.1007/s10803-010-1135-3

  • “A positive AT profile was significantly overrepresented among ADHD children versus controls (18% vs 0.87%; P < .001). ADHD children with the AT profile were significantly more impaired than control subjects in psychopathology, interpersonal, school, family, and cognitive domains. […] A substantial minority of ADHD children manifests ATs, and those exhibiting ATs have greater severity of illness and dysfunction.”

  • “Parents/teachers completed DSM-IV-referenced rating scales for 6–12 year old children with ASD (N = 115), the majority of whom were boys (86 %). Most children were rated by parents (81 %) or teachers (86 %) as being socially or academically impaired by symptoms of at least one psychiatric disorder. The most common impairing conditions (parent/teacher) were attention-deficit/hyperactivity disorder (67 %/71 %), oppositional defiant disorder (35 %/33 %), and anxiety disorder (47 %/34 %), and the combined rates based on either informant were generally much higher.”

  • “A significant percentage of children with ASD seeking services at clinical centers present with comorbid symptoms of ADHD, with rates ranging between 37% (Gadow et al., 2006) and 85% (Lee and Ousley, 2006) across studies conducted in the United States and Europe (Rao and Landa, 2013). ADHD was the third most common disorder identified in a community sample of 5–17 years old children (Leyfer et al., 2006), with 31% of the sample meeting full ADHD criteria and another 24% with subsyndromal ADHD symptoms. […]
    Recent research suggests that many individuals with ADHD may experience social impairments that are more consistent with those observed in ASD. In children with a primary diagnosis of ADHD, the level of autistic symptomatology corresponded to the severity of ADHD subtype; children with the combined type of ADHD-demonstrated the most autistic symptoms (Reiersen et al., 2007). In a study recently published by Kotte et al. (2013), a positive autistic traits (AT) profile operationalized from the CBCL, was significantly overrepresented among ADHD children vs. controls (18 vs. 0.87%; P < 0.001).
    Recent research suggests many individuals with ADHD may experience social impairments consistent with those observed in ASD. Santosh and Mijovic (2004) characterized the social impairments in children with ADHD as associated with either relationship difficulty (conduct and affective problems), or with social-communication difficulty. Children with the latter were more likely to exhibit repetitive behaviors, speech and language impairment, and developmental problems similar to ASD. Other investigators have described deficient empathy and facial affect recognition in children with ADHD (Sinzig et al., 2008; Uekermann et al., 2010). Other studies have also pointed at the increased rate of autistic symptoms in samples of children with ADHD. Grzadzinski et al. (2011) confirmed the presence of a sub group of children with ADHD and elevated ratings of core ASD traits not accounted for by ADHD or behavioral symptoms. The ADHD group with AT revealed greater ODD behaviors than those with ADHD-only. Most of the studies conducted in middle or late childhood have shown that a substantial proportion of children with ADHD show significant autistic symptoms (Santosh and Mijovic, 2004; Holtmann et al., 2007; Nijmeijer et al., 2008).”

  • “Seventy-six percent of youth with ASD met Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria for ADHD. The clinical presentation of ADHD in youth with ASD was predominantly similar to its typical presentation including age at onset (3.5 ± 1.7 vs. 4.0 ± 1.9; p = .12), distribution of diagnostic subtypes, the qualitative and quantitative symptom profile, and symptom severity. Combined subtype was the most frequent presentation of ADHD in ASD youth. […] Despite the robust presentation of ADHD, a significant majority of ASD youth with ADHD failed to receive appropriate ADHD treatment (41% vs. 24%; p = .02). A high rate of comorbidity with ADHD was observed in psychiatrically referred youth with ASD, with a clinical presentation typical of the disorder.”
    • Symptom Profile of ADHD in Youth With High-Functioning Autism Spectrum Disorder: A Comparative Study in Psychiatrically Referred Populations – Joshi, Faraone, Wozniak, Tarko, Fried, Galdo, Furtak & Biederman (2014) – https://doi.org/10.1177/1087054714543368

  • “In this and prior studies of clinic-referred samples of youth with ASD, ADHD is the most frequent comorbid psychiatric condition identified (Frazier et al. 2001; Goldstein and Schwebach 2004; Yoshida and Uchiyama 2004; Lee and Ousley 2006; de Bruin et al. 2007; Lecavalier 2006; Skokauskas and Gallagher 2012). The present findings add to a growing body of literature demonstrating the substantial comorbid presence of ADHD and ASD that is associated with higher levels of impairment, supporting the DSM-V revision whereby diagnoses of ASD and ADHD are no longer mutually exclusive (Sikora et al. 2012). Clinical recognition of ADHD in youth with ASD is critical to providing affected children with appropriate treatments for both disorders.”
    • Examining the Clinical Correlates of Autism Spectrum Disorder in Youth by Ascertainment Source – Joshi, Faraone, Wozniak, Petty, Fried, Galdo, Furtak, McDermott, Epstien, Walker, Caron, Feinberg & Biederman (2014) – https://doi.org/10.1007/s10803-014-2063-4
    • Referencing:

  • “Results suggest that increasing ASD symptomatology within ADHD is associated with a more severe phenotype in terms of oppositional, conduct and anxiety symptoms, lower full-scale IQ, working memory deficits and general motor problems. These associations persisted after accounting for ADHD severity, suggesting that autistic symptomatology independently indexes the severity of comorbid impairments in the context of ADHD.”

  • “A majority of children with ASD (31–95%) have significant symptoms of inattention and/or hyperactivity/impulsivity, not all children with ASD have these symptoms. […] Goldstein and Schwebach found that just over half (59%) of the children with ASD met diagnostic criteria for ADHD. Of the children with ASD who met criteria for ADHD, 26% met diagnostic criteria for ADHD-Combined type and 33% met diagnostic criteria for ADHD-Inattentive type. Because not all of the children with ASD demonstrated significant evidence of ADHD-like characteristics, the authors concluded that the two disorders are likely independent from each other. Similar to the Goldstein and Schwebach study, Sinzig et al. found that the Inattentive subtype of ADHD was the most prevalent ADHD subtype in children with ASD. In the Sinzig study, 46% met criteria for ADHD-Inattentive type, 32% for ADHD-Combined type and 22% for ADHD-Hyperactive/Impulsive type.”

  • “We investigated the longitudinal relationship between socio-economic disadvantage (SED) and trajectories of emotional and conduct problems among children with autism spectrum disorder (ASD) who had comorbid attention deficit/hyperactivity disorder (ADHD; ASD + ADHD) or not (ASD − ADHD). The sample was 209 children with ASD who took part in the UK’s Millennium Cohort Study. Trajectories of problems across ages 3, 5 and 7 years were analyzed using growth curve models. The ASD − ADHD group decreased in conduct problems over time but the ASD + ADHD group continued on a high trajectory. Although SED was not a risk factor for ASD + ADHD, it was associated with elevated emotional problems among children with ASD + ADHD. This effect of SED on emotional problems was not attenuated by parenting or peer problems.”
    • Poverty and the Growth of Emotional and Conduct Problems in Children with Autism With and Without Comorbid ADHD – Flouri, Midouhas, Charman & Sarmadi (2015) – https://doi.org/10.1007/s10803-015-2456-z

  • “A review of the 33 studies that were identified showed evidence that the prevalence of symptoms of ADHD in children with ASD was 33-37%. The comorbid condition presents a greater deficit in inhibitory control, attention and working memory. Likewise, in social cognition, the clinical features of ADHD increase the difficulties in cases of ASD. Moreover, the clinical profile of ASD + ADHD is seen to be more severe than that of pure ADHD or ASD, and delayed language development and the intensity/frequency of tantrums are symptoms that are a valuable aid in identification at early ages.”
    • Comorbidity of autism spectrum disorder and attention deficit with hyperactivity. A review study – Berenguer-Forner, Miranda-Casas, Pastor-Cerezuela & Rosello-Miranda (2015) – https://europepmc.org/article/med/25726822

  • “We employed a clinical sample of young children with ASD, with and without intellectual disability, to determine the rate and type of psychiatric disorders and possible association with risk factors. We assessed 101 children (57 males, 44 females) aged 4.5–9.8 years. 90.5 % of the sample met the criteria. Most common diagnoses were: generalized anxiety disorder (66.5 %), specific phobias (52.7 %) and attention deficit hyperactivity disorder (59.1 %).”
    • Co-occurring Psychiatric Disorders in Preschool and Elementary School-Aged Children with Autism Spectrum Disorder – Salazar, Baird, Chandler, Tseng, O’Sullivan, Howlin, Pickles & Simonoff (2015) – https://doi.org/10.1007/s10803-015-2361-5

  • “In the total sample, 52.0 % of the patients had at least one psychiatric disorder comorbid to ADHD and 26.2 % had two or more comorbid disorders. The most frequent comorbid disorders were disorders of conduct (16.5 %), specific developmental disorders of language, learning and motor development (15.4 %), autism spectrum disorders (12.4 %), and intellectual disability (7.9 %). […] The study provides evidence that comorbidity with mental disorders is developmentally sensitive. Furthermore, the study shows that particular attention should be given to patients with neurodevelopmental disorders such as autism and intellectual disability in future longitudinal analyses. These disorders are very frequent in patients with ADHD, and the affected patients might follow a different course than patients without these disorders.”
    • Comorbid mental disorders in children and adolescents with attention-deficit/hyperactivity disorder in a large nationwide study – Jensen & Steinhausen (2015) – https://doi.org/10.1007/s12402-014-0142-1

  • “Of the ADHD sample, 21 % met ASD cut-offs on the ADOS and 30 % met ASD cut-offs on all domains of the ADI-R.”
    • Parent-reported and clinician-observed autism spectrum disorder (ASD) symptoms in children with attention deficit/hyperactivity disorder (ADHD): implications for practice under DSM-5 – Grzadzinski, Dick, Lord & Bishop (2016) – https://doi.org/10.1186/s13229-016-0072-1

  • “Congruently, the current study was focused on non-clinical participants and we found a prevalence of 57.7%. These findings support the hypothesis that the comorbidity with ADHD may constitute a distinctive phenotype of ASD, and these children may be at a greater risk of involvement and socially adaptive problems. Moreover, ADHD is a condition that produces high academic dysfunctionality and therefore, exacerbates the academic and social needs of children who present comorbidity with ASD. This is important because participants with both conditions are given various treatments or strength requirements than those which have only ASD. These results are congruent with a growing number of studies that have shown that both pathologies can co-exist”
    • Psychiatric comorbidities in autism spectrum disorder: A comparative study between DSM-IV-TR and DSM-5 diagnosis – Romero, Manuel Aguilar, Del-Rey-Mejias, Mayoral, Rapado, Pecina, Barbancho, Ruiz-Veguilla & Pablo Lara (2016) – https://doi.org/10.1016/j.ijchp.2016.03.001

  • “A substantial minority of youth with ADHD (15-25%) demonstrate ASD traits and symptoms with 12.4% having an ASD diagnosis. Conversely, ADHD is the most common comorbidity in children with ASD with comorbidity rates in the 40-70% range.”

  • “In a population of children diagnosed with ASD, the rate of ADHD + ASD was 42% and the rate of ADHD + ASD + ID was 17%, resulting in a 59% total comorbidity rate of ADHD and ASD. Statistically significant differences in age when parents first wondered about problems with development, age when medical assistance was first sought, and age of reported ASD diagnosis were found between the ASD + ADHD and all other groups, with the ASD + ADHD being older. Average age at diagnosis was over 6 years for children with ASD + ADHD but close to 2.5 years for children with ASD only.”

  • “Data are drawn from baseline assessments from 201 children with autism spectrum disorder who participated in a community effectiveness trial across 29 publicly funded mental health programs. Non-autism spectrum disorder diagnoses were assessed using an adapted Mini-International Neuropsychiatric Interview, parent version. Approximately 92% of children met criteria for at least one non-autism spectrum disorder diagnosis (78% attention deficit hyperactivity disorder, 58% oppositional defiant disorder, 56% anxiety, 30% mood).”
    • Characterizing psychiatric comorbidity in children with autism spectrum disorder receiving publicly funded mental health services – Brookman-Frazee, Stadnick, Chlebowski, Baker-Ericzen & Ganger (2017) – https://doi.org/10.1177/1362361317712650

  • “Rates of visits with coded-ASD per 100 outpatient medical visits increased from 0.04% to 0.82% from 1994 to 2009. Factors associated with an ASD diagnosis included male gender, lack of private insurance, white race, and later study period. The most frequent comorbid behavioral diagnoses were ADHD, anxiety, disruptive behavior, and mood disorders. Older age was linked to an increased likelihood of having a comorbid behavioral diagnosis and using psychotropic medications. Geographic region was also associated with having a comorbid behavioral diagnosis, and psychotropic use was linked to have a behavioral comorbidity. Comorbidities with the highest rates of psychotropic use were ADHD, mood, and anxiety disorders.”
    • Autism spectrum disorders and their treatment with psychotropic medications in a nationally representative outpatient sample: 1994–2009 – Kamimura-Nishimura, Froehlich, Chirdkiatgumchai, Adams, Fredstrom & Manning (2017) – https://doi.org/10.1016/j.annepidem.2017.06.001

  • “All mental health conditions were statistically significant; disruptive impulse conduct disorders, attention-deficit/hyperactivity disorders (ADHD) and anxiety disorders were the most prevalent among ASD cases during the pre-diagnostic period and had stronger associations with ASD risk than depression, adjustment disorders, tic disorder and other mental health conditions, each of which had low prevalence among ASD cases (<1%) during the pre-diagnostic period.”
    • Medical Conditions in the First Years of Life Associated with Future Diagnosis of ASD in Children – Alexeeff, Yau, Qian, Davignon, Lynch, Crawford, Davis & Croen (2017) – https://doi.org/10.1007/s10803-017-3130-4

  • “In this large population-based case-control study, we found a high prevalence of ADHD symptoms as measured by the ABC in preschool-aged children with ASD. There was a clear difference in hyperactivity subscale items across diagnostic groups, and significant associations between these ADHD symptoms and higher levels of other cognitive/behavioral deficits in children with ASD.
    The first aim of this work was to determine the prevalence of ADHD symptoms across our diagnostic groups. Approximately 40% of children with ASD fell in the top quartile of the hyperactivity subscale, as well as within our exploratory hyperactivity/impulsivity and inattention subdomains, based on the distribution in the full study sample. […] Another striking result in our study was the consistency of associations between presence of ADHD symptoms and evidence of greater cognitive/behavioral impairments in children with ASD. Though not statistically significant for all subscales, higher overall ADHD symptoms corresponded to poorer adaptive functioning, and cognitive abilities, a finding also previously reported for older children (Yerys et al. 2009).”
    • Inattention and hyperactivity in association with autism spectrum disorders in the CHARGE study – Lyall, Schweitzer, Schmidt, Hertz-Picciotto & Solomon (2017) – https://doi.org/10.1016/j.rasd.2016.11.011
    • Referencing:
      • Attention deficit/hyperactivity disorder symptoms moderate cognition and behavior in children with autism spectrum disorders – Yerys, Wallace, Sokoloff, Shook, James & Kenworthy (2009) – https://doi.org/10.1002/aur.103

  • “In both cohorts, people with ASD were four times more likely to be male and more than two thirds were between the age of 5 and 17 (Table 1). Autistic disorder (ICD-9 299.0x) was the predominant ASD diagnosis code. The commercially insured sample was geographically balanced across the US. The most frequent psychiatric comorbidity was ADHD (around 40%), followed by anxiety disorder (commercial) or intellectual disability (Medicaid).”
    • Psychiatric comorbidities and use of psychotropic medications in people with autism spectrum disorder in the United States – Houghton, Ong & Bolognani (2017) – https://doi.org/10.1002/aur.1848

  • “The QICDSS shows that the prevalence of ASD has risen steadily over the past decade to approximately 1.2% (n = 16,940) of children and youths aged 1 to 17 years in 2014 to 2015. The same prevalence was obtained using Ministry of Education data. Common medical comorbidities included congenital abnormalities of the nervous system, particularly in the first year of life. Psychiatric comorbidity was much more highly prevalent, especially common mental disorders like anxiety and attention-deficit/hyperactivity disorder.“
    • Prevalence and Correlates of Autism Spectrum Disorders in Quebec – Binta Diallo, Fombonne, Kisely, Rochette, Vasiliadis, Vanasse, Noiseux, Pelletier, Renaud, St-Laurent & Lesage (2017) – https://doi.org/10.1177/0706743717737031

  • “Approximately one in eight children currently diagnosed with ADHD was also diagnosed with ASD. Children diagnosed with both disorders had greater treatment needs, more co-occurring conditions, and were more likely to have a combined hyperactive/impulsive and inattentive ADHD subtype.”

  • “A total of 226 children were defined as ASD screen positive (3.6%), 66 girls (2.1% of all girls) and 160 boys (5.1% of all boys). […] Almost half of the children (43.6%) met the symptom criteria for ADHD.”
    • Autism traits: The importance of “co-morbid” problems for impairment and contact with services. Data from the Bergen Child Study – Posserud, Hysing, Helland, Gillberg & Lundervold (2018) – https://doi.org/10.1016/j.ridd.2016.01.002

  • “The rate of clinically elevated ADHD and anxiety symptoms in ASD was 62.7 and 44.6%, respectively, and symptom severity was significantly greater than the non-clinical sample. […] Regression analyses for prediction of ADHD and anxiety symptoms revealed that being a female and having lower adaptive skills scores predicted higher Inattention severity; being older, having better cognition, and more severe Restrictive Repetitive Behavior symptoms predicted more severe HI symptoms; being older and having more severe social impairments predicted higher anxiety scores. A regression analysis for the prediction of adaptive skills revealed that in addition to cognition and autism severity, the severity of Inattention symptoms added to the prediction of overall adaptive skills. In light of these findings, clinicians should diagnose these comorbidities in ASD early on, and provide effective interventions to reduce their negative impact on functioning, thereby improving outcome.”
    • The Presence of Comorbid ADHD and Anxiety Symptoms in Autism Spectrum Disorder: Clinical Presentation and Predictors – Avni, Ben-Itzchak & Zachor (2018) – https://doi.org/10.3389/fpsyt.2018.00717

  • “We performed a cross-sectional study of children with ASD who were enrolled in the Interactive Autism Network, an Internet-mediated, parent-report, autism research registry. Children ages 6 to 17 years with a parent-reported, professional, and questionnaire-verified diagnosis of ASD were included. […] There were 3319 children who met inclusion criteria. Of these, 1503 (45.3%) had ADHD. Comorbid ADHD increased with age (P < .001) and was associated with increased ASD severity (P < .001). A generalized linear model revealed that children with ASD and ADHD had an increased risk of anxiety disorder (adjusted relative risk 2.20; 95% confidence interval 1.97–2.46) and mood disorder (adjusted relative risk 2.72; 95% confidence interval 2.28–3.24) compared with children with ASD alone. Increasing age was the most significant contributor to the presence of anxiety disorder and mood disorder.”

  • “There is no doubt that there is an increasing recognition of the comorbidity of ASD and ADHD. Both conditions are being identified and diagnosed more often than in the past which may relate to an increased awareness, changes in diagnostic criteria and reporting practices particularly for ASD [7]. Previous editions of DSM [8] did not allow clinicians to diagnose ASD in a child with ADHD. However, in 2013, DSM-5 [1] removed this prohibition in response to research that has provided clear evidence that the two conditions can co-exist. Despite the earlier prohibition, clinical reports of comorbidity have been published in the decade prior to DSM-5. ADHD has been reported to be the most common psychiatric condition diagnosed in children with high-functioning ASD (IQ > 70) [9]. Other studies reported that 59 to 83% of youth with ASD also present with ADHD [10, 11]. Research subsequent to DSM-5 examining ASD/ADHD in children [12, 13] reports estimates of comorbid ASD/ADHD that concur with previous findings that ADHD is the most common psychiatric comorbidity in children with ASD with comorbidity rates of 40 – 70%. Around one third of 4–18-year olds with ADHD have clinically elevated levels of ASD symptoms [14].

    More recently, attention has been paid to the prevalence of ASD/ADHD in 6–17-year olds. Joshi et al. [15] found a high rate of comorbid ADHD in youth with ASD (up to 83%) that concurs with earlier findings that ADHD is the most common psychiatric condition in referred populations of youth with ASD [16, 17]. Mansour [18] recently reported that higher levels of ADHD symptom severity, rather than severity of ASD symptoms, were associated with a greater number of comorbid psychiatric diagnoses in school-aged children with ASD. Joshi et al. [15] also reported that in a sample of youth with ASD, rates of ADHD were equally high and evenly distributed among subtypes of ASD, that is those with intellectual disability (IQ < 70) and those without intellectual disability (> 70). In children with ADHD, increasing levels of autistic symptoms have been associated with more oppositional, conduct and anxiety symptoms as well as lower IQ [19].

    However, despite the robust presentation of ADHD symptoms, a significant proportion of youths with ASD/ADHD fail to receive ADHD-specific treatment. Hartman et al. [20] commented on the biased focus of research on children with ASD/ADHD rather than older individuals and reported findings from their study that investigated individuals aged from birth to 84 years. ASD/ADHD symptoms were at their highest during adolescence and lower in early childhood and old age. They recommend that a lifespan approach is necessary to understand the symptomatology of comorbid ASD and ADHD and further, that in light of their finding that adolescents with ASD/ADHD were more severely affected, that they should be a focus for future research and the development of treatment options.”
    • Trends in the Overlap of Autism Spectrum Disorder and Attention Deficit Hyperactivity Disorder: Prevalence, Clinical Management, Language and Genetics – May, Brignell, Hawi, Brereton, Tonge, Bellgrove & Rineheart (2018) –  https://doi.org/10.1007/s40474-018-0131-8
    • Referencing:
      • [7] – Explaining the Increase in the Prevalence of Autism Spectrum Disorders – The Proportion Attributable to Changes in Reporting Practices – Hansen, Schendel & Parner (2015) – https://doi.org/10.1001/jamapediatrics.2014.1893
      • [8] – Diagnostic and Statistical Manual of Mental Disorders, 4th Edition – American Psychiatric Association (2000) – https://doi.org/10.1176/appi.books.9780890420249.dsm-iv-tr
      • [1] – Diagnostic And Statistical Manual Of Mental Disorders, Fifth Edition – American Psychiatric Association (2013) – https://doi.org/10.1176/appi.books.9780890425596
      • [9] – Prevalence of Comorbid Psychiatric Disorders in Children and Adolescents with Autism Spectrum Disorder – Tsai (2014) – https://doi.org/10.1016/j.jecm.2014.10.005
      • [10] – Comorbid Psychiatric Disorders in Children with Autism: Interview Development and Rates of Disorders – Leyfer, Folstein, Bacalman, Davis, Dinh, Morgan, Tager-Flusberg & Lainhart (2006) – https://doi.org/10.1007/s10803-006-0123-0
      • [11] – Kiddie-SADS Reveals High Rates of DSM-IV Disorders in Children and Adolescents with Autism Spectrum Disorders – Gjevik, Eldevik, Fjæran-Granum & Sponheim (2011) – https://doi.org/10.1007/s10803-010-1095-7
      • [12] – Comorbid mental disorders in children and adolescents with attention-deficit/hyperactivity disorder in a large nationwide study – Jensen & Steinhausen (2014) – https://doi.org/10.1007/s12402-014-0142-1
      • [13] – Co-occurring Psychiatric Disorders in Preschool and Elementary School-Aged Children with Autism Spectrum Disorder – Salazar, Baird, Chandler, Tseng, O’Sullivan, Howlin, Pickles & Simonoff (2015) – https://doi.org/10.1007/s10803-015-2361-5
      • [14] – Parent-reported and clinician-observed autism spectrum disorder (ASD) symptoms in children with attention deficit/hyperactivity disorder (ADHD): implications for practice under DSM-5 – Grazadzinski, Dick, Lord & Bishop – https://doi.org/10.1186/s13229-016-0072-1
      • [15] – Symptom Profile of ADHD in Youth With High-Functioning Autism Spectrum Disorder: A Comparative Study in Psychiatrically Referred Populations – Joshi, Faraone, Wozniak, Tarko, Fried, Galdo, Furtak & Biederman (2014) – https://doi.org/10.1177/1087054714543368
      • [16] – Psychiatric disorders in individuals with high-functioning autism and Asperger’s disorder: Similarities and differences 0 Mukaddes, Herguner & Tanidir (2010) – https://doi.org/10.3109/15622975.2010.507785
      • [17] – Attention Deficit/Hyperactivity Disorder in Children and Adolescents With Autism Spectrum Disorder: Symptom or Syndrome? – Sinzig, Walter & Doepfner (2009) – https://doi.org/10.1177/1087054708326261
      • [18] – ADHD severity as it relates to comorbid psychiatric symptomatology in children with Autism Spectrum Disorders (ASD) – Mansour, Dovi, Lane, Loveland & Pearson (2017) – https://doi.org/10.1016/j.ridd.2016.11.009
      • [19] – Autistic traits in children with ADHD index clinical and cognitive problems – Cooper, Martin, Langley, Hamshere & Thapar (2013) – https://doi.org/10.1007/s00787-013-0398-6
      • [20] – Changing ASD-ADHD symptom co-occurrence across the lifespan with adolescence as crucial time window: Illustrating the need to go beyond childhood – Hartman, Geurts, Franke, Buitelaar & Rommelse (2016) – https://doi.org/10.1016/j.neubiorev.2016.09.003

  • “We argue that overlapping symptoms between autism spectrum disorder and attention-deficit/hyperactivity disorder might delay a formal diagnosis of autism either by leading to a misdiagnosis of attention-deficit/hyperactivity disorder or by making it difficult to identify the presence of co-occurring autism spectrum disorder conditions once an initial diagnosis of attention-deficit/hyperactivity disorder has been obtained. Current findings highlight the need to recruit multidimensional and multidisciplinary screening procedures to assess for potential emerging autism spectrum disorder hallmarks in children and adolescents diagnosed or presenting with attention-deficit/hyperactivity disorder symptoms.”
    • Delayed autism spectrum disorder recognition in children and adolescents previously diagnosed with attention-deficit/hyperactivity disorder – Kentrou, de Veld, Mataw & Begeer (2018) – https://doi.org/10.1177/1362361318785171

  • “In this systematic review and meta-analysis, we searched MEDLINE, Embase, PsycINFO, Scopus, Web of Science, and grey literature for publications between Jan 1, 1993, and Feb 1, 2019, in English or French, that reported original research using an observational design on the prevalence of co-occurring mental health conditions in people with autism and reported confirmed clinical diagnoses of the co-occurring conditions and autism using DSM or ICD criteria. […] From our meta-analyses, we found overall pooled prevalence estimates of 28% (95% CI 25–32) for attention-deficit hyperactivity disorder”
    • Prevalence of co-occurring mental health diagnoses in the autism population: a systematic review and meta-analysis – Lai, Kassee, Besney, Bonato, Hull, Mandy, Szatmari & Ameis (2019) – https://doi.org/10.1016/S2215-0366(19)30289-5

  • “The most common individual CoCs were DD general (10.8% in SY2002, 14.9% in SY2010), language disorder (18.6% in SY2002, 23.4% in SY2010), DD motor (9.1% in SY2002, 15.7% in SY2010) and ADHD (9.4% in SY2002, 13.6% in SY2010).”
    • Trends in documented co-occurring conditions in children with autism spectrum disorder, 2002–2010 – Rubenstein, Schieve, Wiggins, Rice, Van Naarden Braun, Christensen, Durkin, Daniels & Lee (2019) – https://doi.org/10.1016%2Fj.ridd.2018.08.015

  • “We explored patterns of concomitant psychiatric disorders in a large sample of treatment-seeking children and adolescents with autism spectrum disorder (ASD). […] The rates of concomitant disorders across studies were: ADHD 81%, ODD 46%, CD 12%, any anxiety disorder 42%, and any mood disorder 8%. Two or more psychiatric disorders were identified in 66% of the sample. Of those who met criteria for ADHD, 50% also met criteria for ODD and 46% for any anxiety disorder.”
    • An exploration of concomitant psychiatric disorders in children with autism spectrum disorder – Lecavalier, McCracken, Aman, McDougle, McCracken, Tierney, Smith, Johnson, King, Handen, Swiezy, Arnold, Bearss, Vitiello & Scahill (2019) – https://doi.org/10.1016/j.comppsych.2018.10.012

  • “Children with ADHD and ASD experience more difficulty in daily situations as compared to those with only one disorder. Co-occurrence of ADHD and ASD is associated with a lower quality of life and poorer adaptive functioning as compared to children with ASD only. In addition, co-occurring ADHD and ASD may be less responsive to standard treatments for either disorder than individuals with only one form of the disorders. At present there are few reports regarding developmental trajectories when ADHD and ASD co-occur and it may be important to examine whether early ASD treatment can influence the stability of ADHD symptoms and vice versa.”
    • Neurodevelopmental Disorders and Adaptive Functions: A Study of Children With Autism Spectrum Disorders (ASD) and/or Attention Deficit and Hyperactivity Disorder (ADHD) – Scandurra, Gialloreti, Barbanera, Scordo, Pierini & Canitano (2019) – https://doi.org/10.3389/fpsyt.2019.00673

  • “ADHD symptoms predicted poor adaptive behavior scores in the full ASD sample (caregiver ratings, ΔR2 = 0.033–0.119; teacher ratings, ΔR2 = 0.113–0.163) and in the subset with subclinical ADHD symptoms (caregiver ratings, ΔR2= 0.023–0.030; teacher ratings, ΔR2 = 0.097–0.159) after controlling for confounds. Age correlated negatively with ADHD symptoms (r = −0.21) and adaptive behaviors (−0.17 < r < −0.39) in the full ASD sample. Age did not moderate the effect of ADHD symptoms on adaptive behaviors. […] ADHD symptoms predict poorer adaptive behavior for autistic children across settings, even for children with subclinical co-occurring ADHD symptoms. Findings support a Research Domain Criteria framework that behavioral impairments and functional outcome measures exist along a continuum.”
    • Attention-Deficit/Hyperactivity Disorder Symptoms Are Associated With Lower Adaptive Behavior Skills in Children With Autism – Yerys, Bertollo, Pandey, Guy & Schultz (2019) – https://doi.org/10.1016/j.jaac.2018.08.017

  • “We examined the prevalence of comorbid Attention-Deficit/Hyperactivity Disorder (ADHD) parsed by DSM-5 presentation in clinic-referred youth with Autism Spectrum Disorder (ASD) without intellectual disability (ID). We compared common rating scales to determine which most effectively identified comorbid ADHD. […] Sixty-one percent of the study sample met DSM-5 criteria for an attention disorder. ADHD, Combined (ADHD-C) represented the largest proportion of ADHD diagnoses (76.8%), followed by Inattentive (ADHD-I;19.7%), Hyperactive/Impulsive (.02%), and Un-/Other Specified (.02%).”

  • “ASD and ADHD have shared genetic heritability and are both associated with shared impairments in social functioning and executive functioning. Quantitative and qualitative differences exist, however, in the phenotypic presentations of the impairments which characterize ASD and ADHD. For ASD interventions to be maximally efficacious, comorbid ADHD needs to be considered (and vice versa). […] The research on ASD and ADHD suggests some overlap between the two disorders yet enough differences to indicate that these conditions are sufficiently distinct to warrant separate diagnostic categories.”

  • “To summarize, autistic traits are common among children with ADHD, even if different ADHD subtypes are associated with different levels of social impairments. Namely, combined ADHD subtypes show the strongest association with autistic symptoms of all domains, whereas ASD dimension of RRB is more correlated with hyperactivity / impulsivity rather than inattention and this latter is equally associated with RRB and SIC. There’s also a longitudinal pattern in the association of these disorders, with ADHD being a better predictor of ASD rather than the reverse association. On the whole, these data may be taken into account in prevention and in the development of intervention programs, also considering the different symptomatology of these conditions and its impact on treatment.”

  • “Only 15.1% of children with ASD held a dual diagnosis of DCD, whereas 58% of children with ASD had a communication disorder (ie, articulation problems, pragmatic communication disorder, language delay/disorder, or mutism), 40.8% had ADHD, and 17.9% had a learning disability.”

  • “This study examined the prevalence of ADHD symptoms and anxiety as reported by parents and teachers for 180 preschool children (ages 4–5) and school-aged children (ages 6–7) with ASD […] Parents reported elevated ADHD symptoms in 22% of preschool children and 45% of school-aged children, while teachers reported elevations in 20 and 24%, respectively.”

  • “Of the 3246 included participants, the majority, 65.2%, (25.7% females) were diagnosed with combined ADHD (mean age 12.14 ± 2.86 years), followed by 18.4% with the inattentive type (34.2% females, mean age 13.71 ± 2.37 years), the hyperactive/impulsive type 4.4%, (20.8% females, mean age 12.10 ± 2.98 years) and 3.4% were diagnosed with ADHD not otherwise specified (32.7% females, mean age 12.24 ± 3.01 years). The proportion of missing data on ADHD subtype was 8.6%. Approximately 38% of the total sample were female. The largest group 51.8% were in the age range 13–17 years, the mean for the total group was 12.5 ± 2.9 years (range: 4–17 years). […] Disregarding combinations with other diagnoses, the frequencies for the separate diagnoses were as follows: ASD 29.4% […] ASD is most closely linked to impaired psychosocial function, learning and tic disorders having low or no impact respectively. The persistent difficulties in social interaction and communication in ASD in combination with ADHD characteristics of distractibility and impulsiveness may lead to more pronounced social impairments explaining the decrease in CGAS scores.”

  • “The purpose of the current study was to examine the prevalence of attention deficit hyperactivity disorder (ADHD) symptoms among young children with autism spectrum disorder (ASD), child and parent-related demographic and clinical correlates of ADHD symptoms, and the relationships between co-occurring mental health problems and ADHD symptoms. Data for this cross-sectional study came from 979 toddlers and preschoolers, ages 1.5–5 years, with ASD. […] There were 418 (43%) children in the low ADHD symptom group, 294 (30%) in the moderate ADHD symptom group, and 267 (27%) in the high ADHD symptom group.”
    • Attention deficit hyperactivity disorder symptoms in young children with autism spectrum disorder – Hong, Singh & Kalb (2020) – https://doi.org/10.1002/aur.2414

  • “Anxiety disorders, mood disorders, obsessive-compulsive disorder (OCD), ADHD, and oppositional defiant disorder (ODD) represent co-occurring psychopathologies most commonly associated with a diagnosis of ASD […] The co-occurrence of ASD and ADHD has been demonstrated in multiple studies (Lecavalier et al., 2019; Leitner, 2014; Rommelse, Franke, Geurts, Hartman, & Buitelaar, 2010; Simonoff et al., 2008; Taurines et al., 2012). Reported prevalence rates of diagnostic co-occurrence are somewhat variable, in part because only recently the DSM-5 criteria for concurrent diagnosis of the disorders were allowed (American Psychiatric Association, 2013). Recent prevalence estimates of concurrent ASD and ADHD are veiy high (i.e., 81% in a large treatment-seeking sample; Lecavalier et al., 2019). Further, the clinical impact of co-occurring ASD and ADHD appeal’s significant (Gadow, DeVincent, & Pomeroy, 2006; Zablotsky, Bramlett, & Blumberg, 2020). Individuals with ASD and co-occurring ADHD are at greater risk for concomitant anxiety and mood disorders (Gordon-Lipkin, Marvin, Law, & Lipkin, 2018; Lecavalier et al., 2019).”

  • “This ambiguity in sample definitions might have resulted in misinterpretations of ASD or ADHD traits and in reduced awareness of the specific characteristics of the comorbid population (from now on referred to as ASD + ADHD). Particularly, social cognition traits that highly affect the quality of life of both ASD and ADHD are thought to be more severely impaired in comorbid ASD + ADHD cases. Also, comorbid individuals seem to respond differently to existing interventions as they cause challenges in medical treatment and may benefit less from social skills trainings. Finally, comorbid cases have been proposed to present a more complex phenotype with more severe deficits in the clinical and cognitive domains, including social deficits. Taken together, there is a need for valid biomarkers characterizing and differentiating ASD, ADHD, and ASD + ADHD groups.”
    • Comorbidity Matters: Social Visual Attention in a Comparative Study of Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder and Their Comorbidity – Ioannou, Seernai, Stefanou, Riedel, Tebartz van Elst, Smyrnis, Fleischhaker, Biscaldi-Schaefer, Boccignore & Klein (2020) – https://doi.org/10.3389/fpsyt.2020.545567

  • “The co-occurrence of ASD and ADHD was not formally recognized until the fifth revision of the Diagnostic and Statistical Manual of Mental Disorders (Diagnostic and Statistical Manual of Mental Disorders, fifth edition, 2013). The co-occurrence between both disorders is reported between 20 to 70% (Brookman-Frazee et al., 2018; Joshi et al., 2017; Llannes et al., 2020; Lyall et al., 2017; Salazar et al., 2015). This broad range depends on the type of sample (clinical or community, age), the evaluation procedures, the type of informants, the diagnostic criteria utilized as well as specific characteristics of the individuals such as their cognitive level. A recent meta-analysis showed an overall pooled prevalence estimates of 28% for ADHD in ASD population (Lai et al., 2019) that increased with age and ASD severity (Gordon-Lipkin et al., 2018). In addition to being fairly frequent, an increasing body of literature suggests that ASD+ADHD comorbidity increases vulnerability and clinical complexity. Indeed, in the presence of ADHD symptoms, autism seems to be generally associated with more severe impairments in executive functioning, theory of mind, adaptive functioning, greater psychosocial problems and poorer quality of life (Antshel, 2013; Berenguer-Forner et al., 2015; Leitner., 2014; Taurines et al., 2012).”
    • Cognitive, social, and behavioral manifestations of the co-occurrence of autism spectrum disorder and attention-deficit/hyperactivity disorder: A systematic review – Rosello, Martinez-Raga, Mira, Pastor, Solmi & Cortese (2021) – https://doi.org/10.1177/13623613211065545
    • Referencing:
      • Characterizing psychiatric comorbidity in children with autism spectrum disorder receiving publicly funded mental health services – Brookman-Frazee, Stadnick, Chlebowski, Baker-Ericzen & Ganger (2017) –https://doi.org/10.1177/1362361317712650
      • Symptom Profile of ADHD in Youth With High-Functioning Autism Spectrum Disorder: A Comparative Study in Psychiatrically Referred Populations – Joshi, Faraone, Wozniak, Tarko, Fried, Galdo, Furtak & Biederman (2014) – https://doi.org/10.1177/1087054714543368
      • Parent and Teacher Reports of Comorbid Anxiety and ADHD Symptoms in Children with ASD – Llanes, Blacher, Stavropoulos & Eisenhower (2020) – https://doi.org/10.1007/s10803-018-3701-z
      • Inattention and hyperactivity in association with autism spectrum disorders in the CHARGE study – Lyall, Schweitzer, Schmidt, Hertz-Picciotto & Solomon (2017) – https://doi.org/10.1016/j.rasd.2016.11.011
      • Co-occurring Psychiatric Disorders in Preschool and Elementary School-Aged Children with Autism Spectrum Disorder – Salazar, Baird, Chandler, Tseng, O’Sullivan, Howlin, Pickles & Simonoff (2015) – https://doi.org/10.1007/s10803-015-2361-5
      • Prevalence of co-occurring mental health diagnoses in the autism population: a systematic review and meta-analysis – Lai, Kassee, Besney, Bonato, Hull, Mandy, Szatmari & Ameis (2019) – https://doi.org/10.1016/S2215-0366(19)30289-5
      • Anxiety and Mood Disorder in Children With Autism Spectrum Disorder and ADHD – Gordon-Lipkin, Marvin, Law & Lipkin (2018) – https://doi.org/10.1542/peds.2017-1377
      • The comorbidity of ADHD and autism spectrum disorder – Antshel, Zhang-James & Faraone (2014) – https://doi.org/10.1586/14737175.2013.840417
      • Comorbidity of autism spectrum disorder and attention deficit with hyperactivity. A review study – Berenguer-Forner, Miranda-Casas, Pastor-Cerezuela & Rosello-Miranda (2015) – https://europepmc.org/article/med/25726822
      • The co-occurrence of autism and attention deficit hyperactivity disorder in children – what do we know? – Leitner (2014) – https://doi.org/10.3389/fnhum.2014.00268
      • ADHD and autism: differential diagnosis or overlapping traits? A selective review – Taurines, Schwenck, Westerwald, Sachse, Siniatchkin & Freitag (2012) – https://doi.org/10.1007/s12402-012-0086-2

  • “Comorbidity with attention-deficit/hyperactivity disorder (ADHD) is very common in autism spectrum disorder (ASD), worsening the developmental trajectory of ASD. […] The results revealed that the pooled current and lifetime prevalence rates of ADHD among ASD were 38.5 % (95 % CI 34.0–43.2) and 40.2 % (95 % CI 34.9–45.7), respectively.”

  • “The prevalence of ADHD in ASD varied from 28 to 83% across studies. Studies using DSM-IV reported lower rates of ADHD in contrast to ones using DSM-5 criteria. On average a quarter of subjects with ASD had ADHD comorbidity based on current population-based studies we included”
    • Population-Based Psychiatric Comorbidity in Children and Adolescents With Autism Spectrum Disorder: A Meta-Analysis – Mutluer, Genc, Morey, Eser, Ertinmaz, Can & Munir (2022) – https://doi.org/10.3389%2Ffpsyt.2022.856208

  • “Evidence suggests that children with ASD and co-occurring ADHD are a high-need population (Hong et al., 2020; Zablotsky et al., 2020). They appear to have poorer outcomes overall and reduced response to social skills intervention than children with either diagnosis alone (Elwin et al., 2020; Fleming et al., 2020; McDougal et al., 2020). Co-occurring ADHD is associated with more severe ASD symptoms, lower adaptive functioning, and greater cognitive impairment compared to an ASD diagnosis alone (Yerys et al., 2019; Zachor & Ben-Itzchak, 2020). While emotional and conduct challenges for children with ASD appear to reduce overtime, these challenges appear to increase for children with ASD + ADHD (Flouri et al., 2015). Co-occurring ADHD also appears to further exacerbate stress, financial, and time burdens for families (Dovgan & Mazurek, 2019).”
    • Age of Diagnosis for Co-occurring Autism and Attention Deficit Hyperactivity Disorder During Childhood and Adolescence: a Systematic Review – Sainsbury, Carrasco, Whitehouse, McNeil & Waddington (2022) – https://doi.org/10.1007/s40489-022-00309-7
    • Referencing:
      • Attention deficit hyperactivity disorder symptoms in young children with autism spectrum disorder – Hong, Singh & Kalb (2020) – https://doi.org/10.1002/aur.2414
      • The Co-Occurrence of Autism Spectrum Disorder in Children With ADHD – Zablotsky, Bramlett & Blumberg (2017) – https://doi.org/10.1177/1087054717713638
      • Symptoms and level of functioning related to comorbidity in children and adolescents with ADHD: a cross-sectional registry study – Elwin, Elvin & Larsson (2020) – https://doi.org/10.1186/s13034-020-00336-4
      • Neurodevelopmental multimorbidity and educational outcomes of Scottish schoolchildren: A population-based record linkage cohort study – Fleming, Salim, Mackay, Henderson, Kinnear, Clark, King, McLay, Cooper & Pell (2020) – https://doi.org/10.1371/journal.pmed.1003290
      • Profiles of academic achievement and attention in children with and without Autism Spectrum Disorder – McDougal, Riby & Hanley (2020) – https://doi.org/10.1016/j.ridd.2020.103749
      • Attention-Deficit/Hyperactivity Disorder Symptoms Are Associated With Lower Adaptive Behavior Skills in Children With Autism – Yerys, Bertollo, Pandey, Guy & Schultz (2019) – https://doi.org/10.1016/j.jaac.2018.08.017
      • From Toddlerhood to Adolescence, Trajectories and Predictors of Outcome: Long-Term Follow-Up Study in Autism Spectrum Disorder – Zachor & Ben-Itzchak (2020) – https://doi.org/10.1002/aur.2313
      • Poverty and the Growth of Emotional and Conduct Problems in Children with Autism With and Without Comorbid ADHD – Flouri, Midouhas, Charman & Sarmadi (2015) – https://doi.org/10.1007/s10803-015-2456-z
      • Impact of multiple co-occurring emotional and behavioural conditions on children with autism and their families – Dovgan & Mazurek (2019) – https://doi.org/10.1111/jar.12590

  • “​​According to the scientific literature, 50 to 70% of individuals with autism spectrum disorder (ASD) also present with comorbid attention deficit hyperactivity disorder (ADHD)”

Last updated: Sunday June 26, 2022

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