Autonomic Dysfunction and Anxiety in Autism

For many years now, I have been interested in the role of the autonomic nervous system (ANS) in autism spectrum disorder (ASD). The ANS innervates our internal organs and takes care of those bodily functions that are carried out automatically, without our conscious awareness, e.g., sweating, pupillary dilation, breathing, and heart rate.  Signs of autonomic disturbances in ASD include sleep disturbances, baseline (tonic) pupillary dilation, altered skin conductance, and lack of heart rate regulation to potentially stressful stimuli.  My own belief is that autonomic dysfunction underlies the chronic generalized anxiety experienced by a majority of autistic individuals.  This is of importance as measures of autonomic arousal, as well as autonomic cardiac responses regulation profiles, could be useful in distinguishing subgroups of autistic individuals and how we treat them.  Several trials using beta-blockers (e.g., Inderal) may target overeractivation of the sympathetic nervous system by blockading its effect on the heart. I hope that these trials may provide better results than treatment with anxiolytic medication. The latter drugs are prescribed primarily for the short-term use, are prone to abuse, and have withdrawal effects.

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The autonomic nervous system (ANS) is directly involved in manifestations of affect, emotional expression, facial gestures, vocal communication, and social engagement behaviors. Indeed, the ANS is responsible for multiple physiological responses.  Dysfunction of this system is often hypothesized as contributing to abnormalities of cognitive, emotional, and behavioral responses in children with autism.  Cardiac under-reactivity during socially engaging situations results in lower behavioral flexibility and reduced attentional capacity to relevant stimuli, – a skill critical for social communication development.

I have always found it of interest that sympathetic over-activation is often associated with anxiety disorders. Children and adolescents with ASD are known to manifest anxiety symptoms; a very common complaint in the clinical settings. A majority of children with ASD meet criteria for at least one anxiety disorder. However, I would like to add that symptoms of anxiety may also be related to reduced functional connectivity between frontal cortex and limbic system, as a weakened normative frontal inhibition of limbic system is usually observed in ASD.

Anxiety is one of the most pressing clinical concerns in autism due to its negative impact on the physical and emotional well-being of an autistic individual, the high prevalence in this population, and its bidirectional relationship with other core deficits.  Researchers have emphasized that atypical autonomic arousal can explain some of the core symptoms of ASD, in particular stereotyped repetitive behaviors, avoidance of social interaction, and impaired attention.

Development of new neuromodulation and neurotherapeutic methods aimed at reducing autonomic arousal in children with autism is thus an important clinical research initiative.  Unfortunately, the federal government provides little in terms of funding for these initiatives even when the same may have immediate and profound effects in the lives of our children.

 

8 responses to “Autonomic Dysfunction and Anxiety in Autism

  1. Very interesting concepts, will spend more time with this article. Initially what comes up for me is some of the most effective tools I have found that actually help me be more functional, as a person within the spectrum, are practices that work with our autonomic/unconscious like: walking the Wu Wei Circle (Taoist practice), working with the subtle bodies and meditation practices and dance/movement (cross-cultural). At the heart of these practices/systems is breath-work, understanding our faculties of perception and processing information-experience and mastering/understanding the power of our attention (first and second). For me pharmaceuticals, talk therapy and such don’t take me where I want to go. I want to explore, dance and fully engage with my functionality along with my dysfunction (two sides of the same coin).

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  2. I’m autistic and I’m working with a functional medicine practitioner to treat my autonomic dysfunction (POTS and orthostatic hypotension). There are sets of exercises and chiropractic manipulations that exist that bring the vestibular system back into balance, and in the process, help heal autonomic dysfunction. It’s a slow process, but I’m doing far better now than before. My anxiety is significantly reduced except in overload situations. There’s no need to worry about allocating thousands of dollars to research drugs that will inevitably have unintended adverse effects (commonly known as side effects) when treatment already exists.

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    • Very glad to hear you have found an effective system and practitioner to work with. There are many traditional and contemporary practices/systems that can help, perhaps a more effective use of funding would be making these systems more accessible to those in need? As well as more direct support as needed.

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  3. Manuel,is it possible the parasympathetic dysfunction you are talking about can manifest as neurocardiac disorders that an cause chronic or acute heart failure?Cardiac conduction disorder and heart failure has been a problem for me for most of my life.The link here between cardiac under-reactivity,and social interaction,would explain a lot for me.I don’t believe the heart-brain connection is a subject that has been sufficiently studied in autism research.You might be able to stake out a whole new area of research for yourself if you were to study this.

    Even though my autism has been largely eradicated by treating cerebral folate deficiency,I am still quite shy,and have difficulty in social situations,especially those involving small talk.

    Parasympathetic dysfunction is also linked to autoimmune disease,which I have,possibly a rare form of genetic systemic lupus.And we know how common autoimmune disease is in autism.

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    • You hit on several areas of which we are deeply interested. Yes, the parasympathetic dysfunction may be related to cardiac disorders. We have some data indicating lack of variability in heart rate which may predispose a person, among others, to acute heart failure. Emily is pursuing the possible connection with immune abnormalities. If we had a better research infrastructure we could have accomplished a lot more.

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  4. Can my son (6yr old ASD) still participate in the TMS research study and get the treatments? If so, can you please direct me to the person I should talk to?
    Thanks

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