Sympathetic Nervous System Function in Autism: A Systematic Review
Publication Title: Basal Sympathetic Nervous System Functioning in Autism: A Systematic Review of Neurochemical Studies
Summary
- Question
- This study aimed to clarify whether individuals with autism spectrum disorder (ASD) exhibit chronic hyperarousal, heightened physiological responses to stress, or typical sympathetic nervous system (SNS) functioning. The researchers conducted a systematic review of neurochemical studies to examine basal and reactive SNS activity in ASD.
- Why it Matters
- Understanding SNS functioning in autism is essential because altered arousal impacts behaviors like anxiety, aggression, and sleep disturbances. These factors influence both the quality of life for individuals with autism and clinical care approaches. Clarifying whether SNS activity is atypical could help refine therapeutic strategies and inform broader discussions on neurobiology and healthcare for autism.
- Methods
The researchers performed a systematic review of 26 studies from databases including PubMed, Scopus, and Web of Science. They extracted and compiled reported urinary and plasma levels of norepinephrine (NE), epinephrine (EPI), and their metabolites to assess basal SNS activity. Plasma measures of NE and EPI were assumed to evaluate acute stress reactivity, while urinary data minimized stress-related measurement bias.
- Key Findings
The review found no significant group differences in basal SNS functioning between individuals with ASD and controls based on urinary and plasma metabolite levels. However, plasma levels of NE and EPI were elevated in individuals with autism during acute stress (e.g., venipuncture). Nighttime reductions in SNS activity were similar in both groups, suggesting typical diurnal patterns.
- Implications
- The findings suggest that basal SNS activity is not atypical in ASD, but heightened reactivity to stress may be present. This distinction has implications for understanding anxiety and stress management in autism. Moreover, typical SNS functioning may mitigate concerns about its role in increased cardiovascular risk observed in ASD, though episodic stress responses may still contribute.
- Next Steps
- Future research should focus on individual differences in SNS functioning within autism populations and explore links between SNS measures and behavioral traits. Studies employing broader stress paradigms and incorporating distribution analyses of neurochemical measures could further clarify subgroup-specific responses.
- Funding Information
- This research was not supported by any specific funding sources, as stated in the paper. Yale University also provided funding and support for this research.
Full Citation
Authors
Krisha Neupane
First AuthorGeorge Anderson, PhD
Last AuthorSenior Research Scientist in the Child Study Center and in Laboratory Medicine
Other Authors
Research Themes
Concepts
- Plasma epinephrine;
- Systematic review;
- Heightened reactivity to stress;
- Chronic state;
- Sympathetic nervous system function;
- Nervous system function;
- Plasma NE;
- Sympathetic function;
- State of hyperarousal;
- MethodsThe PubMed;
- Urine measurements;
- Neurochemical studies;
- Sympathetic system;
- Web of Science databases;
- Epinephrine;
- Metabolite measurements;
- Reactivity to stress;
- Nervous system;
- Response to stress situations;
- Independent reviewers;
- SNS function;
- Norepinephrine;
- ASD group;
- Diagnostic terms;
- Sympathetic measures