Peripheral Sympathetic and Parasympathetic Activity in ASD with and without Comorbid Anxiety

Background: Anxiety disorders are one of the most common comorbidities among individuals with autism spectrum disorder (ASD). While anxiety disorders have been thoroughly characterized from a psychophysiological perspective, this is not yet true for the psychophysiological manifestations of anxiety in ASD. Both pathologies are underlined by abnormal physiological activity.

Objectives: To assess similarities and differences in the peripheral sympathetic (i.e., electrodermal) and parasympathetic (i.e., heart rate variability) activity of children with ASD with and without comorbid anxiety and matched controls.

Methods: Seventy-five children and adolescents between 7 and 17 years of age were recruited. Thirty-seven were diagnosed with ASD, of which 22 with comorbid anxiety. Thirty-eight were typically developing controls (TDC), of which 16 were diagnosed with one or more anxiety disorders. All watched natural-scene movies while the physiological activity was recorded.

Results: Peripheral sympathetic activity within individuals with anxiety was found to be higher in TDC as compared to the ASD group. Higher vagal activity was reported in the TDC non-anxiety group as compared to both ASD groups. A multinomial regression model including such physiological measures and parent reports on anxiety (SCARED) and ASD symptoms (SCQ) allowed to classify 73% of cases across the 4 groups.

Conclusions: Besides supporting the inclusion of psychophysiological indicators when examining the relationship between anxiety and ASD, this study highlights the need for more research on how to best conceptualize, evaluate, and treat children with ASD with and without comorbid anxiety.