What’s in a name? Intolerance of uncertainty, other uncertainty-relevant constructs, and their differential relations to worry and generalized anxiety disorder^*

* Preliminary findings from this research were presented at the 2014 meeting of the British Association for Behavioural and Cognitive Psychotherapies (Birmingham, UK).

Abstract

A number of studies have examined the association of intolerance of uncertainty (IU) to trait worry and generalized anxiety disorder (GAD). However, few studies have examined the extent of overlap between IU and other psychological constructs that bear conceptual resemblance to IU, despite the fact that IU-type constructs have been discussed and examined extensively within psychology and other disciplines. The present study investigated (1) the associations of IU, trait worry, and GAD status to a negative risk orientation, trait curiosity, indecisiveness, perceived constraints, self-oriented and socially prescribed perfectionism, intolerance of ambiguity, the need for predictability, and the need for order and structure and (2) whether IU is a unique correlate of trait worry and of the presence versus absence of Probable GAD, when overlap with other uncertainty-relevant constructs is accounted for. N = 255 adults completed self-report measures of the aforementioned constructs. Each of the constructs was significantly associated with IU. Only IU, and a subset of the other uncertainty-relevant constructs were correlated with trait worry or distinguished the Probable GAD group from the Non-GAD group. IU was the strongest unique correlate of trait worry and of the presence versus absence of Probable GAD. Indecisiveness, self-oriented perfectionism and the need for predictability were also unique correlates of trait worry or GAD status. Implications of the findings are discussed, in particular as they pertain to the definition, conceptualization, and cognitive-behavioral treatment of IU in GAD.

Keywords:

• Intolerance of uncertainty
• worry
• generalized anxiety disorder
• process
• construct

Acknowledgements

The authors would like to thank Nick Carleton, Colleen Carney, Michel J. Dugas, Katie Fracalanza, and Mark Freeston for discussions regarding the present study. We also would like to thank the reviewers at Cognitive Behaviour Therapy, who provided thoughtful feedback on this manuscript.

Notes

* Preliminary findings from this research were presented at the 2014 meeting of the British Association for Behavioural and Cognitive Psychotherapies (Birmingham, UK).

1. Readers should note that a widely used short form of the IUS, the IUS-12 (Carleton, Norton, & Asmundson, 2007) also exists. We used the original 27-item IUS as this measure was developed within the context of a GAD theoretical framework and has been used the most in the testing of the IU Model of GAD. However, given the growing body of literature on the short form, we extracted the 12 items that constitute the IUS-12 and retested the study hypotheses using the total score and scores on its two factors, Prospective Anxiety and Inhibitory Anxiety. The results of these analyses can be obtained from the first author. Individuals in the Probable GAD group scored significantly higher on the total IUS-12, and on each of the subscales namely, Prospective Anxiety and Inhibitory Anxiety, than did individuals in the non-GAD group. We then performed two sets of the regression analyses reported in this manuscript. The first set was with the IUS-12 total score as a predictor, instead of the IUS-27 total score. In the second set of regressions, we isolated the scores for the Prospective Anxiety and Inhibitory Anxiety dimensions to get a better understanding of the relations of the IUS-12 factors to trait worry and GAD status. Overall, the findings were nearly the same as reported for the full scale IUS. IU as measured by the IUS-12 total score was the strongest unique correlate of trait worry and GAD status. The non-IUS unique correlates in this new analysis were the same as those reported in this manuscript. The subscale analyses showed that scores on the Prospective Anxiety subscale, but not on the Inhibitory Anxiety subscale, predicted unique variance in trait worry and in GAD status, suggesting that the relations of IUS-12 to worry and GAD are largely accounted for by the items reflecting Prospective Anxiety, defined as “fear and anxiety based on future events” (Carleton et al., 2007). However, given that the 12 items were merely extracted and not administered on their own as an independent measure it cannot be concluded from the present findings that the IUS-12 is equivalent to the IUS-27 since responses to the 12 items that constitute the short form may have been influenced in unknown or unexpected ways by responses to the other 15 items.

2. We would like to acknowledge the anonymous reviewer who suggested that we include this point.

3. We would like to acknowledge the anonymous reviewer who suggested that we include this point.