Associations Between Autistic Traits, Sensory Processing Abnormalities and Anxiety Symptoms in Adults

Background: Sensory processing abnormalities are increasingly recognized to be a key symptom of autism spectrum disorders (ASDs). Unusual sensory experiences, including both hypersensitivity and hyposensitivity, are hypothesized to underlie many of the characteristic features of ASDs, including repetitive behaviours and stereotypies such as ‘stimming’. Previous studies have reported high rates of sensory features in individuals with an ASD, and recently studies in the general population have found that subclinical ASD traits are also correlated with reports of unusual sensory experiences, consistent with the broad ASD phenotype model.  However, anxiety is also common in ASD and it has been suggested that anxiety mediates the association between ASD and altered sensory processing.

Objectives: We conducted the largest study to date of ASD traits, sensory experiences, and anxiety symptoms, in a sample consisting of adults both with and without an ASD, in order to discover whether ASD traits are associated with sensory symptoms, and to investigate whether anxiety is a mediating factor.

Methods: Participants (n=956) were recruited via online advertisements. Participants provided basic demographic details, details of their ASD diagnosis (if any), and completed the following self-report measures: the Autism Quotient (AQ), Adult/Adolescent Sensory Profile (AASP), Glasgow Sensory Questionnaire (GSQ), Cardiff Anomalous Perception Scale (CAPS), and  Spielberger Trait Anxiety Inventory (STAI). Total scores were calculated, and Pearson’s correlation coefficient was used to calculate bivariate correlations among scores.

Results: Consistent with previous reports, we found that reported sensory symptoms (AASP, GSQ and CAPS) were correlated with autism trait scores (AQ): AASP/AQ: r=0.34; GSQ/AQ: r=0.49; CAPS/AQ: r=0.31 (all p’s<0.001). Further, for the first time in adults, we show that anxiety is also correlated with both AQ scores and with sensory behaviours: STAI/AQ: r=0.48; STAI/AASP: r=0.39; STAI/GSQ: r=0.41; STAI/CAPS: r=0.34 (all p’s<0.001). These correlations remained significant when considering separately only the participants with and without a diagnosis of ASD. Also, we found that both sensory and anxiety symptoms were independently associated with AQ scores, even after covarying for the other (all p’s< 0.001). Furthermore, we show that these results are not accounted for by gender, age, or presence of psychiatric comorbidity.

Conclusions: In adults, autistic traits are associated both with high levels of anxiety, and with sensory processing abnormalities. This was evident across the ASD spectrum and including general population neurotypical controls, confirming that these are important facets of the ASD phenotype. Our results suggest that both anxiety and sensory abnormalities are independently related to ASD, but also associated with each other. This suggests that in individuals with an ASD, abnormalities with sensory processing and anxiety symptoms are linked, but separate, phenomena. Implications for the assessment and treatment of ASD will be discussed.