Intolerance of Uncertainty and Anxiety in Adolescents with Autism Spectrum Disorder

Background: A recent meta-analysis indicated that almost 40% of youth with autism spectrum disorder (ASD) experience significant anxiety symptoms (i.e., clinically-elevated levels of anxiety or at least one DSM-IV anxiety disorder; van Steensel et al., 2011). It has been suggested that fear about unpredictable future events may be particularly problematic for individuals with ASD (Lainhart, 1999). In the anxiety literature, the term intolerance of uncertainty (IOU) has been used to describe negative beliefs about, and reactions to, novel, uncertain, or changing situations (Buhr & Dugas, 2009). It has been suggested that increased IOU may predispose individuals to develop excessive worry (Koerner & Dugas, 2008).

Objectives: To further explore the relationship between anxiety and the unpredictability of future events in ASD we: 1) examined potential differences in IOU and anxiety between adolescents with ASD and typically developing (TYP) comparison participants, and 2) evaluated the relationship between IOU and anxiety in both ASD and TYP participants. 

Methods: To date, 23 youths (aged 12 to 18 years) with ASD and 23 age-, sex-, and IQ-matched comparison participants have completed the study. Two parent-report questionnaires, the Intolerance of Uncertainty Scale for Children (IUSC; Comer et al., 2009) and the Screen for Child Anxiety Related Disorders (SCARED; Birmaher et al., 1997), were completed for each participant. Total raw scores, ranging from 27 to 135 for the IUSC and 0 to 82 for the SCARED, were examined as dependent variables. On these measures, higher scores indicate greater IOU and anxiety symptoms, respectively. As IOU has been hypothesized to be predictive of excessive worry, the Generalized Anxiety Disorder (GAD) subscale of the SCARED was also examined.

Results: Independent samples t-tests were used to compare groups on both parent-report measures. Results revealed significantly higher scores on the IUSC for the ASD group (M=61.59, SD=15.34), compared to the TYP group (M= 38.48, SD=11.54; t(41)=-5.56, p < .01). The same pattern of results was observed for the SCARED total score (ASD: M=17.14, SD=11.99; TYP: M=8.86, SD=6.87; t(41)=-2.76, p<.01) and the SCARED GAD subscale (ASD: M=5.41, SD=4.37; M=2.86, SD=3.27; t(41)=-2.16, p<.05). Pearson’s correlations were used to examine the relationship between IUSC and SCARED scores within each group. For the TYP group, IUSC scores were significantly correlated with SCARED scores for both the total scale (r(21)=.68, p<.01) and the GAD subscale (r(21)=.55, p<.01). However, there were no significant relationships in the ASD group; IUSC with total SCARED (r(22)=.26, p>.05) and GAD subscale (r(22)=.20, p>.05).

Conclusions: As expected, results indicate that youth with ASD have greater IOU and more anxiety symptoms than their TYP peers. Interestingly, we found significant associations between IOU and anxiety in the TYP group, but not the ASD group. These findings suggest that the relationship between these constructs is unique in youths with ASD, relative to their TYP contemporaries. These results have important implications for our understanding of fear about unpredictable future events, and anxiety more generally, in ASD.