Effects of Sensory Sensitivity and Intolerance of Uncertainty on Anxiety in Mothers of Children with Autism Spectrum Disorder

Background:  Parents of individuals with autism spectrum disorders (ASD) consistently report elevated levels of anxiety. Such anxiety may be linked to the stress of managing their child’s ASD symptoms, but it is also likely to be influenced by individual characteristics in the parent. Identifying the influence of individual parent factors is important given that anxiety has negative implications for interpersonal relations. In this study we focus on two key individual traits that are associated with anxiety in the general population; intolerance of uncertainty, defined as a “relatively broad construct representing cognitive, emotional, and behavioral reactions to uncertainty in everyday life situations” (Freeston et al., 1994) and sensory sensitivity, a trait that predisposes individuals to be more sensitive to various stimuli from the social and physical environment.

Objectives: This study examined the relations between anxiety in mother and other personal characteristics of sensory sensitivity and intolerance of uncertainty. Given previous research in general population samples, it was predicted that both IU and sensory sensitivity would have a direct effect on maternal anxiety. However, IU and sensory sensitivity might also have an indirect effect on anxiety according to several different models: the relation between IU and anxiety may be mediated by sensory sensitivity (model 1) or the relation between sensory sensitivity and anxiety may be mediated by IU (model 2).

Methods:   Fifty mothers of children and adolescents with ASD (mean age of children = 10 years 7 months (10.7), SD= 3.10; mean age of mothers = 44.4; SD= 6.3) completed the Hospital Anxiety and Depression Scale (HSP), the Highly Sensitive person scale and the Intolerance of Uncertainty (IU) Scale. None of the mothers had a diagnosis of ASD.

Results:   Almost half (46%) of mothers met the cut-off criterion for clinically significant anxiety; these mothers significantly differed from the non-anxious mothers in terms of their IU (t= 3.01; p= .004; Cohen’s d= .85) and HSP total scores (t= 2.22; p= .03; Cohen’s d= .63). A three-way interrelationship between sensory sensitivity, IU and anxiety was found. In order to characterize the nature of this interrelationship, two mediation analyses were performed using the serial mediation model in PROCESS (Hayes, 2012) testing two above described models. Mediation analyses showed direct effects between anxiety and both IU and sensory sensitivity but a significant indirect effect was found only in model 2 in which IU mediated between sensory sensitivity and anxiety. Our findings supported the second mediation model. In other words, the presence of high sensitivity and a susceptibility to being overwhelmed by environmental stimulation, may lead to an experience of the world as highly unpredictable. Such increased unpredictability could make even the most simple situations and events uncertain and difficult, thereby provoking anxiety.

Conclusions:   This is the first study to characterize the nature of the interrelation between intolerance of uncertainty and sensory sensitivity in predicting the levels of anxiety.