Sensory Processing Sensitivities and Personality in Adults with and without ASD

Background: Although sensory processing sensitivity (SPS) is a criterion of ASD, and adults with ASD describe it as a highly salient part of their experience (Chamak et al., 2008; Henderson & Davidson, 2010; Robledo et al., 2012), no study has examined whether people with ASD are highly sensitive persons (Aron & Aron, 1997). College students with elevated autistic traits also tend to be more highly sensitive (Liss, Mailloux, & Erchull, 2008). Of the Five-Factor Model of Personality (“Big 5”), such sensitivities positively relate to Neuroticism and Openness to Experience (Smolewska, McCabe, & Woody, 2006). The Big 5 accounts for 70 percent of the variance in ASD symptomology at the facet level, as well as clusters that distinguish within the autism spectrum (Schwartzman, Wood, & Kapp, 2013). SPS may similarly help explain personality and heterogeneity within the ASD phenotype.

Objectives: (1) To determine how much correspondence exists between the HSPS and the Big 5 factors in adults with and without ASD (2) To determine the extent to which the HSPS accounts for variability in ASD symptomatology in adults with and without diagnoses of ASD (3) To empirically identify distinct personality and sensory profiles that exist within ASD in terms of HSPS variability.

Methods: A sample of 828 adults (364 with ASD; 464 without) completed an online survey consisting of the Highly Sensitive Person Scale (HSPS; Aron & Aron, 1997), Ritvo Autism Asperger’s Diagnostic Scale Revised (RAADS-R; Ritvo et al., 2010), the International Personality Item Pool Representation of the NEO-PI-R (IPIP-NEO-120; http://ipip.ori.org), and demographic information. The HSPS is a 27-item scale which measures sensory reactivity to stimuli. The RAADS-R is an 80-item self-rated diagnostic scale for measuring autism based on the DSM-IV and ICD-10 diagnostic criteria. The IPIP-NEO-120 is an online, public domain tool for personality measurement which reports the individual level of personality under each of the five domains in the Five-Factor Model.

Results: (1) In adults with ASD, HSPS scores were found to be positively correlated with Neuroticism, and negatively correlated with Extraversion, Conscientiousness, and Agreeableness, while no significant correlation was found with Openness to Experience. Adults with ASD exhibited significantly higher HSPS scores (M=18.86, SD=5.17) than adults without ASD (M=12.21, SD=5.18) at p < .001 (2) HSPS scores accounted for 47.5% of the variance in RAADS-R scores in adults with ASD. (3) Based on k-means cluster analysis, four distinct Big 5 personality subtypes emerged within adults with ASD and each of these clusters exhibited unique sensory profiles in terms of the HSPS, with distinct associations with quality of life indicators.

Conclusions: Information gained from this study further emphasizes the importance of SPS to the “spectrum” nature of ASD. Considering that sensory issues have only recently been added to the ASD diagnosis, and are a relatively small and optional part of the criteria, they robustly contributed to the differences in ASD symptomology. These findings will help provide more targeted support tailored to individual differences.