Anxiety in the Midst of Autism Spectrum Disorder

John D. Herrington, PhD


December 13, 2018

Although our awareness of the impact of autism spectrum disorder (ASD) continues to increase, many aspects are poorly understood by both clinicians and scientists. Individuals with ASD are at elevated risk for a variety of physical and mental health challenges, from gastrointestinal problems to seizures. Anxiety is probably the most common mental health concern among individuals on the spectrum, and in its more severe forms can pose more challenges than ASD symptoms themselves.

John D. Herrington, PhD

Unfortunately, it has been very difficult to identify the prevalence of anxiety in the ASD population. Studies over the past two decades have suggested prevalence rates ranging from approximately 10% to 80%, a range so broad that it suggests inconsistencies in experimental design and measurement. Although rigorous epidemiologic work remains to be done, more recent estimates suggest an anxiety disorder rate of 40% or higher in ASD,[1] about twice the risk one would expect in an individual without ASD. Although more data on specific anxiety disorders in people with ASD are needed, it appears that rates of all anxiety disorders are elevated, including social anxiety, generalized anxiety, separation anxiety (in children), and phobias.

Why Anxiety in ASD Can Be so Elusive

Many of the problems faced by prevalence researchers are shared by those who work with individuals on the autistic spectrum. How do you know whether any specific symptom is related to ASD, or is better accounted for by an anxiety disorder? Because many individuals with ASD have difficulty putting words to their thoughts and feelings, is it better to trust their caregivers when getting information about anxiety symptoms? The problems providers face in identifying anxiety in ASD are loosely categorized here.

Measurement and assessment problems. Although nothing in the formal diagnostic criteria for ASD refers specifically to the presence of anxiety, some of the key symptoms of ASD do appear in anxiety disorders. Whether you classify any given symptom as ASD or anxiety probably has a lot to do with how you ask the question—that is, how you assess the symptom.

One of the most obvious examples of this dilemma relates to the impaired social behavior among individuals with ASD. If a child with ASD is socially withdrawn, is it because the child lacks the motivation or interest to engage with other children (typical of ASD), or is it because the child is actually anxious in social situations (typical of social anxiety)?

In the clinic, the answer to that question could depend to a large extent on how it is asked. For this reason, several research initiatives are under way (some with support from the National Institutes of Health) to develop better questionnaires and assessment instruments that can tease apart these symptoms.

Difficulties expressing thoughts and feelings. Communication difficulties are a cardinal symptom of ASD, and children with ASD frequently have difficulty conveying their emotions to others. This leaves parents and caregivers in a bind: Should one infer the presence of anxiety on the basis of behavior alone (for example, a child running away from a specific situation), even if the child never says outright that he or she is afraid? This poses a major problem among the significant proportion of the ASD population that has limited or no verbal abilities.

Primary versus secondary anxiety. Psychologists and psychiatrists tend to conceptualize anxiety as the experience of fear that is out of proportion with any actual threat. This assumption is made explicit in several anxiety disorder criteria. However, individuals with ASD frequently face a level of adversity that can be difficult for individuals without ASD to relate to. In other words, individuals with ASD may actually be at higher risk for certain types of anxiety-inducing experiences. For example, many individuals with ASD experience significant social rejection, including bullying. Under those circumstances, it can be harder to conclude that social anxiety is necessarily a disproportionate response.

The same can be said of specific phobias. Many individuals with ASD have fears of specific objects and sensory experiences that are out of proportion to the actual threat they pose but may be understandable in terms of the heightened sensory sensitivities that appear to be common in ASD (for example, loud noises or bright lights).

Psychiatry lacks a common terminology that can be used to describe these distinctions; some refer to this distinction as one between "primary" anxiety (where the anxiety itself is the problem) versus "secondary" anxiety (where anxiety is present in the context of some other problem a person presents with). It is understandable that pediatric clinicians would choose not to diagnose someone with an anxiety disorder when it is unclear how disproportionate the presence of fear actually is.

Diagnostic overshadowing. A related but distinct problem in identifying anxiety in people with ASD concerns the presence of behavioral concerns that are more of an immediate obstacle to one's well-being than "internalizing" problems, such as anxiety or emotional discomfort. Many individuals with ASD present with challenging behaviors that pose an immediate problem to their social, academic, and professional development. It is understandable that these behaviors would be front and center in any assessment or intervention that someone with ASD might receive, and that they may overshadow symptoms of anxiety. However, all of those who care for these children should be mindful of the possibility that anxiety actually triggers challenging behaviors.