Monday, March 10, 2014

The Sensory System and Anxiety


Although research suggests that people with autism may experience higher levels of anxiety compared to the general population, the reason isn't fully clear.

One theory considers the relationship between the sensory system and anxiety. As we know, many children with autism are hypersensitive to things such as noisy environments, visually over-stimulating environments, itchy seams or tags in clothing, and so on. Some evidence exists that anxiety is related to sensory hypersensitivity in children with autism. However, it uncertain which one causes the other, or if they are causally related at all.

Sensory Hypersensitivity as a Possible Cause of Anxiety

It is possible that being hypersensitive to sensory stimuli may lead to anxiety. Let's say a child with autism has an unpleasant sensory reaction to loud noises, such as balloons popping. They may become anxious about the experience happening again, particularly in places associated with the stimuli, such as birthday parties (where balloons are commonly found).

If your child or student has a specific sensory experience that bothers him or her, you may be able to help reduce anxiety by making the experience less threatening. For example, if you know you will be attending a birthday party with balloons, your child might be able to wear ear plugs or listen to music. As another example, I had a student who hated the sound of sirens. When his class had a fire truck visit the school, we knew that the firefighters were going to turn on the siren during their presentation. I found out when they would be doing this and reassured my student that I would tell him when to cover his ears.

A child with autism may also have more general sensory reactions, such as any bright lights or loud noises being bothersome. This may cause more frequent anxiety because these stimuli are found in many places. In this case, anxiety can be more debilitating because it impacts the child more frequently and in more environments.

Sensory stimuli that are uncontrollable and unpredictable to the child or happen more frequently may cause the child to remain in a state of hypervigilance (constantly scanning the environment for potential threats). This may create a state of more constant anxiety.

Anxiety as a Possible Cause of Sensory Hypersensitivity

It is also possible that anxiety may lead to sensory issues, instead of the other way around. There is evidence to suggest that hyperarousal and hypervigilance are characteristic of anxiety disorders. Once a potential threat is observed in the environment, an individual with an anxiety disorder may tend to obsessively focus on it, and have trouble thinking about other things. This could possibly contribute to sensory hypersensitivity. If an individual is constantly scanning the environment for potential threats, he or she may be more likely to notice unpleasant sensory stimuli in the environment.

If anxiety is a primary issue that leads to other issues, such as hypersensitivity, it makes sense to directly address the anxiety. Positively Autism's blog posts in the coming weeks will focus on interventions for anxiety in people with autism, such as cognitive behavior therapy.

Potential Limitations of the Theories

So which theory is correct? We don't know. Sensory hypersensitivity could be the cause, but a fear response does not automatically indicate the presence of an anxiety disorder. If anxiety is the cause, then why don't all individuals with autism and anxiety have hyperarousal or sensory hypersensitivity?  It is also possible that anxiety and hypersensitivity are associated, but do not cause each other.

The Brain and Anxiety

It is possible that differences in the brain may also contribute to anxiety. The amygdala is the part of the brain that relates to arousal regulation and possibly social and emotional intelligence. Limbic system dysfunction and differences in the amygdala may both be present in individuals with autism and dysfunction in the limbic system is associated with the development of anxiety.

More research in all of these areas is needed before making more definite conclusions. Our next posts will continue to explore this topic and provide ideas on using this information.


"The Development of Social Anxiety in Adolescents with Autism Spectrum Disorders" by Scott Bellini. Focus on Autism and Other Developmental Disabilities. Volume 21, Number 3, Fall 2006.

"Anxiety Disorders and Sensory Over-Responsivity in Children with Autism Spectrum Disorders: Is There a Causal Relationship?" by Shulamite A. Green and Ayelet Ben-Sasson. Journal of Autism and Developmental Disorders. Volume 40, 2010.

"Exploring the Nature and Function of Anxiety in Youth with Autism Spectrum Disorders" by Jeffrey J. Wood and Kenneth D. Gadow. Clinical Psychology: Science and Practice. Volume 17, Issue 4, December 2010.

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