Comorbid Autism Spectrum Disorder and OCD: Challenges in Diagnosis and Treatment

It can be challenging to distinguish between symptoms of anxiety and symptoms of autism.

Interventions shown to be highly effective in treating symptoms of autism are already limited, but the options shrink even further in the presence of anxiety comorbidities, particularly obsessive compulsive disorder (OCD). Research has been focused not only on identifying a specific anxiety disorder in children and adolescents with autism, but also in distinguishing between the symptoms of each disorder and how to treat each disorder. Although cognitive behavioral therapy (CBT) with various modifications has been shown to be beneficial, the research evaluating CBT includes small populations and a variety of nonstandard modifications.

Prevalence and Symptom Differentiation

Estimates of the prevalence of anxiety, specifically of OCD, among children and adolescents with autism spectrum disorder (ASD) vary widely, from 11% to 84% for any anxiety disorder and from 2.6% to 37.2% for OCD, reported Valentina Postorino, PhD, of Emory University Department of Pediatrics and of the Marcus Autism Center in Atlanta and colleagues.1 They draw particular attention to one meta-analysis of 31 studies, which found a 39.6% prevalence of “clinically elevated levels of anxiety or at least one anxiety disorder” in young individuals with autism.2

“The range of prevalence rates reported for anxiety disorders and OCD in ASD is likely influenced by the clinical heterogeneity of individuals with ASD, including the broad spectrum of intellectual and verbal abilities,” they wrote.

Manifestations of anxiety are likewise highly variable, they noted, “encompassing both classic and unconventional presentations, such as fears of change or novelty, worries surrounding circumscribed or specialist interests, and unusual phobias.”1

Therein lies the challenge: distinguishing between symptoms of anxiety and symptoms of autism because social withdrawal and “ritualistic behaviors” from anxiety can resemble the difficulty with social interaction and the stimming seen in autism. Although it is already challenging to differentiate between these behaviors in nonverbal children with autism, learned attention-seeking or communicative behaviors may confound the differential diagnosis even in children who are verbally adept, Postorino et al pointed out.1

“Behaviors such as screaming, which might reflect manifestations of anxiety in a nonverbal child or a child with limited emotion recognition, might also reflect learned patterns of behaviors aimed at escaping demands, obtaining attention, or other instrumental purposes that are not accompanied by anxious feelings,” they wrote. “In this way, anxiety symptoms may be both altered in presentation and obscured by their co-occurrence with ASD.”

Assessment and Diagnostic Tools

“Many of the currently available measures to evaluate anxiety and OCD were initially developed and standardized for typically developing children,” Postorino et al wrote. “Therefore, it is possible that these measures may not adequately differentiate between autism and anxiety or obsessive-compulsive symptoms.”

The authors include a list of assessments that practitioners can consider, but they urge caution in interpreting them and emphasize the need to gather and consider information from multiple sources, including caregivers and from direct observation.

Evidence favors the following assessments:

  • Child and Adolescent Symptom Inventory (CASI) — designed to exclude symptoms that co-occur with anxiety and ASD
  • Autism Spectrum Disorders-Comorbidity for Adults scale (ASD-CA)
  • Anxiety Scale for Children with Autism Spectrum Disorder (ASC-ASD)
  • Anxiety Disorders Interview Schedule with Autism Spectrum Addendum (ADIS/ASA) — more comprehensive in differentiating anxiety symptoms from those of ASD
  • Autism Comorbidities Interview’s (ACI) adaptation of the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) for youth with ASD — currently validated only for depression, attention-deficit/hyperactivity disorder (ADHD), and OCD sections
  • Children’s Inventory for Psychiatric Syndromes-Parent Version — has high interrater reliability for specific phobias and generalized, separation, and social anxiety; lower agreement for OCD, ADHD, mood disorders, and generalized anxiety disorder  in youth with IQs below 70
  • The possible development of a parent-reported inventory of anxiety symptoms based on 52 items identified in a study published in Autism3

The following tools measure repetitive behaviors reliably, Postorino et al reported:

  • Children’s Yale-Brown Obsessive Compulsive Scales for ASD (CYBOCS- ASD)
  • Autism Diagnostic Interview-Revised (ADI-R)
  • Repetitive Behavior Questionnaire (RBQ)
  • Repetitive Behavior Interview (RBI)
  • Repetitive Behavior Scale-Revised (RRB-R)

Other anxiety questionnaires were not designed for use in children and adolescents with autism and lack consistent evidence in this population:

  • Multidimensional Anxiety Scale for Children (MASC-C)
  • Revised Children’s Anxiety and Depression Scale (RCADS)
  • Screen for Child Anxiety and Related Emotional Disorders (SCARED)
  • Spence Child Anxiety Scale (SCAS)

Analysis of Treatment Interventions

A systematic review published in the Journal of Developmental and Physical Disabilities by Leman Kaniturk Kose, Lise Fox, and Eric A. Storch from the University of South Florida in St. Petersburg analyzed the effectiveness of CBT based on 11 studies, including 3 randomized controlled trials, 1 case controlled study, 2 single subject experimental designs, and 5 case studies.4

Results from all of the studies showed at least some treatment gains, but they included only 170 participants total with substantial variation in age and severity of conditions. All participants with autism had “high-functioning” autism and an IQ above 69. Further, the studies were very heterogenous in terms of procedures, therapy modifications, and outcome measures.

“In all studies, a multicomponent CBT treatment was implemented,” the authors wrote. “The components of CBT typically involved mapping, cognitive restructuring, fear hierarchy development, [exposure and response prevention], and relapse prevention.” There were also 2 studies with emotional literacy education. The number of CBT sessions ranged from 6 to 17.4 sessions over 9 to 21 weeks, with each session lasting from 35 minutes to 2 hours.4

Further, all of the studies used at least 1 and up to 8 of the following 10 modifications, starting with the 5 most common:

  • Parental involvement
  • Increased use of visuals
  • Incorporation of child interests
  • Personalized treatment metaphors and coping statements
  • Self-monitoring
  • Nonverbal and concrete examples
  • Positive reinforcement
  • Use of clear language and instructions
  • Functional Behavioral Assessment Intervention (FBAI)
  • Narratives

Glen Elliott, PhD, MD, chief psychiatrist and medical director of Children’s Health Council in Palo Alto, California, was not persuaded by the review that CBT is very effective for comorbid autism and OCD, given the small population in this review, its substantial limitations, his own limited clinical success with CBT, and the need for the patient’s willing participation in therapy.

“One of the requirements for diagnosis [of] OCD in non-autistic individuals is that the behavior they engage in [is] behavior they don’t want to engage in,” Dr Elliott told Psychiatry Advisor. “They [are] compelled to do it even though they don’t want to do it.”

Autistic repetitive behaviors are different, however. Children and adolescents with autism who have verbal skills often say they feel content with their repetitive behaviors and have no interest in stopping them.

“What they get upset about is when those behaviors are disrupted,” Dr Elliot said. He noted that their responses can range from annoyance to complete meltdowns.

“I think the motivation to do CBT would be much lower with autistic than [with] non-autistic individuals,” he said. “Most of them think, ‘Why should I give this up? It’s fun, it’s who I am, it’s what I do.’ CBT would be a hard sell since all therapy requires some agreement of ‘I have a problem I’d like to see changed.’”

If they do have repetitive behaviors they don’t enjoy, however, CBT may help them reduce those behaviors, Dr Elliott told Psychiatry Advisor. He described the case of a boy who had such elaborate rituals that it took 3 hours to get through a meal and 20 minutes simply to enter his office. After treatment with fluoxetine and haloperidol, those behaviors decreased, freeing up 6 to 8 hours a day for him to be more socially engaged and participate in behavior he actually enjoyed.

In addition, neither of these reports address the distinction between obsessive and perseverative behaviors, Dr Elliott said.

“With perseverative behaviors, it’s not the behavior that’s important but the fact that they started doing it and can’t stop,” he told Psychiatry Advisor. “Both occur, and they both can be responsive to medications, but they’re different.” Perseverative behaviors typically respond better to antipsychotics while [selective serotonin reuptake inhibitors] more effectively treat obsessive behaviors, he said.

Dr Elliott agreed, however, that there is a strong need for evidence-based interventions for comorbid ASD and OCD.

Currently, CBT is at least somewhat effective, Kose et al noted, when “enhanced with modifications such as increased structure in the sessions, visual aids and cues, and considerable parental involvement.”


  1. Postorino V, Kerns CM, Vivanti G, Bradshaw J, Siracusano M, Mazzone L. Anxiety disorders and obsessive-compulsive disorder in individuals with autism spectrum disorder. Curr Psychiatry Rep. 2017;19:92.
  2. van Steensel FJ, Bögels SM, Perrin S. Anxiety disorders in children and adolescents with autistic spectrum disorders: a meta-analysis. Clin Child Fam Psychol Rev. 2011;14(3):302-317.
  3. Bearss K, Taylor CA, Aman MG, et al. Using qualitative methods to guide scale development for anxiety in youth with autism spectrum disorder. Autism. 2016;20:663-672.
  4. Kose LK, Fox L, Storch EA. Effectiveness of cognitive behavioral therapy for individuals with autism spectrum disorders and comorbid obsessive-compulsive disorder: a review of the research. J Dev Phys Disabil. 2018;30:69-87.