Physiological Arousal Is Related to Parent-and Self-Report of Anxiety in Youth with ASD: Preliminary Evidence for the Concurrent Validity of Anxiety Symptoms

Background: High rates of anxiety have been reported among youth with autism spectrum disorders (ASD). Coexisting symptoms of anxiety have the potential to cause substantial clinical impairment for youth with ASD.  However, the diagnostic interview schedules used to assess anxiety in youth with ASD have not been validated in the autism spectrum population, and it is unclear whether the high rates of comorbid anxiety disorders generated by these assessment instruments actually reflect clinical anxiety, or if they reflect a false positive result. Physiological measurement has the potential to serve as an ‘objective’ index of anxiety given the robust relationship between physiological arousal and manifest anxiety in non-ASD populations.

Objectives: The current study aimed to investigate the concurrent validity of anxiety in ASD by examining the correspondence between physiological response and parent- and self-report of anxiety symptoms. If youth with ASD are actually experiencing clinical anxiety, physiological arousal should theoretically correspond with reported symptoms of anxiety.

Methods: Thirty-two youth with ASD (ages 7-14 years) participated in a startle response paradigm to measure physiological indices of fear conditioning. Skin conductance response (SCR) was collected during the first 3 minutes of baseline, prior to presentation of the first stimulus. The final minute of baseline was used for the current analyses. Youth and their parents also completed the Multidimensional Anxiety Scale for Children (MASC; parent and child versions) and the Child and Adolescent Symptom Inventory-4R (CASI). Results from questionnaires were compared to SCR to investigate whether physiological response paralleled patterns of parent- and child-report of anxiety symptoms.

Results:   Correlational analyses revealed strong relationships between baseline SCR and the following subscales of the MASC: Parent Somatic/Autonomic (r = .356, p = .05), Child Anxious Coping (r = .644, p < .01), Child Harm Avoidance (r = .545, p < .01), Child Separation/Panic (r = .459, p < .05), and Child Total score (r = .423, p < .035). Additionally, SCR baseline scores were related to the CASI Separation Anxiety Disorder subscale (r = .439, p < .05).

Conclusions:   Results indicate that there is a correspondence between child- and parent-report of anxiety symptoms and physiological measurement of arousal. This provides preliminary evidence for the validation of anxiety symptoms in youth with ASD. Additional physiological data, including heart rate measurements, will be added to the model to further investigate the concurrent validity of anxiety symptoms in this sample. Results from this study have the potential to provide objective evidence that a proportion of youth with ASD actually experience clinical anxiety, which will in turn aid in proper identification of comorbid symptoms and provision of appropriate treatment for youth on the autism spectrum.