Unit IV: ASD & Psychiatric Co-morbidity

1. Types of Psychiatric Co-morbidity: anxiety, depression

2. Characteristics Psychiatric Co-morbidity

3. Causes of Psychiatric Co-morbidity

4. Management of Psychiatric Co-morbidity

5. Educational implications for ASD children with Psychiatric Co-morbidity



1. Types of Psychiatric Co-morbidity: anxiety, depression

The Centers for Disease Control and Prevention estimates that autism affects 1 in every 59 children in the US. While the core features of autism impair functioning, a significant source of further impairment is comorbid psychiatric disorders. People with autism spectrum disorder (ASD) are more likely than the general population to have comorbid psychiatric disorders. Although prevalence rates vary widely, converging evidence suggests that anxiety disorders and ADHD are most prevalent.

Numerous factors contribute to the increased risk for comorbid psychiatric disorders. People with autism are at higher risk of being bullied and are more likely to experience adverse life events, which can increase stress and risk for depression and anxiety. Cognitive rigidity, problems with emotion regulation, and intolerance of uncertainty associated with ASD can predispose this population to higher levels of anxiety and depression. Emotional regulation deficits may be a transdiagnostic phenomenon that underlies features of ASD as well as anxiety and other psychiatric comorbidities.

Anxiety disorders

Using findings from their meta-analysis, vanSteensel and colleagues5 estimated that 40% of youth with ASD have a comorbid anxiety disorder. Risk factors for developing anxiety that are prevalent in ASD include social skill deficits, sensory sensitivity, cognitive rigidity, heightened physiological arousal, and difficulties regulating stress.

Specific phobias. Specific phobia tends to have an onset in childhood. In most cases the phenomenology of specific phobia in ASD tends to be similar to typically developing youth. However, people with developmental disabilities may also develop fears to unusual objects or situations, such as elevators, vacuum cleaners, etc.

Common phobias found in youth with ASD include loud noises, needles, and crowds. Sensory sensitivities can contribute to specific fears in autism, some of which may not rise to the level of meeting criteria for specific phobia but can contribute to impairment. For example, anxiety about eating food due to food textures, avoidance of clothing due to tactile sensitivity, or fear of loud objects such as vacuums and hairdryers due to noise sensitivity.

Generalized anxiety. Worry related to intense preoccupations, schedules, and environmental changes may be atypical features of anxiety that are important to recognize and ask patients about. Some of these features are captured by Kerns’s6 summation that they represent an “intolerance of uncertainty,” which can mark atypical anxiety in ASD.

Anxiety can present as perseverative questioning and reassurance seeking about an anticipated event or other worry. Repetitive questions used to obtain more information about a restricted interest should be distinguished from questions that are triggered by anxiety. People with ASD can have difficulty verbalizing internal states of anxiety or triggers for anxiety. For those who are non-communicative, an anxiety disorder may have to be considered by inference based on observation, such as persistent resistance to entering crowded rooms.

Obsessive compulsive disorder. Repetitive behaviors and restricted interests in ASD can be difficult to distinguish from the compulsions and obsessions of OCD. In OCD, obsessions are recurrent, intrusive thoughts that are distressing, and compulsive behaviors in OCD are bothersome, unwanted, and serve the function of attempting to alleviate the obsessional content.

Repetitive behaviors in ASD (eg, lining up objects, following the same routine, watching the same video) are generally a preferred or comforting activity, although they can lead to problematic behaviors or irritability when the person is interrupted or needs to stop. In addition, the most common forms of compulsions in OCD: hand washing, cleaning, making things “just right” are distinct from the typical repetitive behaviors of ASD, such as hand flapping, body rocking, and finger flicking.

People with ASD can have difficulty articulating obsessive thoughts and describing whether a behavior is aimed at reducing anxiety. The ACI adapted the criteria for OCD to allow caregivers to infer the mental experiences of people who exhibit compulsive behaviors. For example, caregivers could be asked if a compulsive behavior appeared to be aimed at reducing anxiety or linked to recurrent thoughts. Using this criteria Leyfer and colleagues4 found that 37% of their sample met criteria of OCD. In a different study by Simonoff and colleagues,7 the assessment tool did not allow for caregivers to make this inference and the prevalence of OCD was estimated at 8.2%.

Social anxiety. Diagnosis of social anxiety in ASD requires that a person with ASD is avoiding social interaction due to a fear of potential negative outcome rather than just a lack of interest in social interaction, which is a common core feature of ASD. In older higher-functioning youth social anxiety can develop as awareness of differences from peers increases.


Diagnosis of depression in neurotypical youth typically relies on self-report of mood symptoms such as feelings of sadness, hopelessness, or decreased self-esteem. Describing these internal states can be difficult for many people with ASD, particularly those with limited verbal skills.

Magnuson and Constantino8 developed a framework for assessment of depression in ASD. For people with limited verbal skills or difficulties verbalizing feelings, increased self-injurious behavior, decreased self-care, labile moods, decreased interest in special interests, and regression of skills were observable behaviors associated with depression. For verbal youth with ASD, insight into ASD symptoms and their impact on functioning, awareness of being teased or being different from peers, social rejection, and low self-efficacy were risk factors for depression.


2. Characteristics Psychiatric Co-morbidity

Diagnostic splitting comes at the risk of spurious comorbidity (attributing a single set of symptoms toward criteria for several disorders). Symptoms such as sleep disturbance, psychomotor changes, and poor concentration in the setting of depression can also, theoretically, be counted as symptom criteria for other conditions described in DSM,increasing the likelihood of multiple diagnoses. One strategy used in DSM-III to reduce spurious comorbidity arising from diagnostic splitting was the introduction of diagnostic hierarchies. For example, the criteria for agoraphobia indicate that the diagnosis should not be given if the characteristic avoidant behavior is really due to obsessive-compulsive disorder.


3. Causes of Psychiatric Co-morbidity

Comorbidity can occur for a variety of reasons. It may be a chance occurrence or be due to the conjunction of independent risk factors; or it may develop because two disorders have shared or overlapping risk factors, or because one disorder causes the other; or the comorbid condition may be a multiform expression of one of the pure disorders, or a third independent disorder. It follows that the best approach for dealing with comorbidity depends on why a given pair of disorders tends to co-occur.

A hierarchical approach is useful if the comorbid condition is a multiform expression of one of the pure disorders. For example, major depressive episodes are almost invariably a complication of dysthymia. Thus, there may not be any advantages to diagnosing a comorbid major depressive disorder in patients with dysthymia. Hierarchies may be also useful if one disorder causes the other, unless the second disorder has additional clinical implications after it develops.

It's not uncommon for people to suffer from two disorders or illnesses at once. Comorbidity in mental illness can include a situation where a person receives a medical diagnosis that is followed by the diagnosis of a mental disorder (or vice versa), or it can involve the diagnosis of a mental disorder that is followed by the diagnosis of another mental disorder.3

A 2009 large cross-sectional national epidemiological study of comorbidity of mental disorders in primary care in Spain published in the Journal of Affective Disorders showed that among a sample of 7936 adult patients, about half had more than one psychiatric disorder.4

Furthermore, in the U.S. National Comorbidity Survey, 51% of patients with a diagnosis of major depression also had at least one anxiety disorder and only 26% of them had no other mental disorder.However, in the Early Developmental Stages of Psychopathology Study, 48.6% of patients with a diagnosis of major depression also had at least one anxiety disorder and 34.8% of them had no other mental disorder.


4. Management of Psychiatric Co-morbidity

Treatment of comorbid psychiatric conditions in ASD warrants a multimodal approach with contributions from caretaker education (applied behavioral analysis); psychotherapy; pharmacology; sensory, speech, and language interventions; and other disciplines depending on the individual’s history and presentation. Although a review of all of these modalities is beyond the scope of this article, some of the evidence and resources for CBT and pharmacotherapy for psychiatric comorbidity in ASD follow.

Cognitive behavioral therapy. CBT has been shown to reduce anxiety in children with ASD and anxiety disorders. Effective modifications to traditional CBT for youth with ASD have included increased parent involvement to promote generalization, incorporation of visual aids, making sessions highly structured and predictable, increased practice of skills, and explicit teaching of social skills as part of the therapy.11,12 Use of the child’s restricted interests can make the therapy more salient, help explain therapeutic concepts, create concrete metaphors, and reinforce participation.

ASD-specific CBT programs for anxiety include Multimodal Anxiety and Social Skills Intervention (MASSI), Face Your Fears, and Behavioral Interventions for Anxiety in Children With Autism (BIACA). Programs targeting executive functioning, mindfulness, and emotion regulation have also been found to reduce anxiety.

Pharmacological interventions. There are currently no medications for the core symptoms of ASD. Pharmacologic interventions for comorbid psychiatric conditions may help to alleviate associated symptoms and allow better engagement for the individual in educational and psychosocial treatments.

Targets for medication may include but are not limited to anxiety, impulsivity, hyperactivity, sleep problems, mood instability, depression, aggression, and self-injurious behavior. The American Academy of Child and Adolescent Psychiatry (AACAP) Practice Parameter on ASD13 provides a summary of ran-
domized controlled trials of medications to treat comorbid psychiatric conditions in ASD; the AACAP14 provides an overview of medication approaches by symptom area and guidelines for parent-provider discussion. 


5. Educational implications for ASD children with Psychiatric Co-morbidity

Comorbidity in ASD is frequently associated with severe impairment. Recognition and treatment of specific syndromes is highly encouraged, in order to improve general functioning and alleviate symptoms. The presence of a comorbid condition should be considered when there are changes from baseline functioning or with new onset symptoms when no other medical or environmental cause is found. Assessment of comorbid condition requires skills and expertise with the ASD population. A comprehensive approach, including information from several sources, specific diagnostic tools adjusted to the ASD population, and emerging interventions may contribute to successful diagnosis and treatment.

The problems raised by psychiatric comorbidity cannot be resolved on an a priori basis. They require data on the nature of comorbidity between specific sets of disorders. As a result, there is no single solution to the problem of comorbidity. Rather, different solutions will be required for different combinations of disorders. As the nature of comorbidity is elucidated, it will undoubtedly lead to significant revisions in the categories and boundaries in the psychiatric nomenclature.