Intolerance of Uncertainty

1.8.1 Defining intolerance of uncertainty

Worriers frequently couch their worries in the form of ‘what if?’ questions. Given that most worries are based on negative things that might happen in the future, it is difficult for the individual to know whether they will or won’t occur. This ‘not knowing’ is experienced as an unpleasant state and gives rise to IU. Birrel, Meares, Wilkinson and Freeston (2011) chart the changes in the way IU has been defined. Initially conceived out of the literature on intolerance of ambiguity (cf. Furnham & Ribchester, 1995), the definition has expanded following new insights in the way that IU is linked to worry, the processing biases that are present in those experiencing IU, and the nature of IU as a cognitive vulnerability factor for GAD. Ladouceur, Blais, Freeston, and Dugas (1998) define IU as “the way in which an individual perceives information in uncertain situations and responds to this information with a set of cognitive, emotional and behavioral reactions” (p. 141). Koerner and Dugas (2008) extended this definition by considering IU as a dispositional cognitive vulnerability factor for worry. They define IU as a “dispositional characteristic that arises from a set of negative beliefs about uncertainty and its connotations and consequences” (p. 631).

1.8.2 Intolerance of uncertainty and processing biases

High IU individuals hold processing biases that result in the perception of ambiguous or uncertain events as threatening and intolerable (Butler & Mathews, 1983, 1987), despite the low probability of such events actually occurring (Ladouceur, Talbot, & Dugas, 1997). Significantly, given these processing biases, high IU individuals also perceive negative events as more probable in uncertain situations than low IU individuals (MacLeod, Williams, & Bekerian, 1991). In addition, high IU individuals seek more information before making decisions that they are confident with (Carleton, Sharpe, & Asmundson, 2007).

1.8.3 Associations between intolerance of uncertainty and worry

A number of studies have demonstrated that IU correlates with trait worry2 _{(e.g., Buhr}

& Dugas, 2006). In Dugas et al.’s (1998) cognitive model of GAD, IU plays a central role, and is posited to drive ‘what if…?’ questioning. Also incorporated in the model are beliefs about worry, poor problem orientation, and cognitive avoidance. Dugas et al. (1998) tested their model to see if these variables could successfully discriminate individuals with and without GAD. IU accounted for the most variance in terms of whether an individual had a diagnosis of GAD or not.

Berenbaum (2010) included IU in his two-phase model of worrying. In this initiation- termination model, the first phase is concerned with threat perceptions, which initiate worrying. The second phase is associated with factors involved in the termination of worry, which Berenbaum (2010) argued is closely related to the acceptance of uncertainty. Consequently, IU is likely to prolong worry bouts as individuals struggle to accept uncertainty.

1.8.4 A causal role for intolerance of uncertainty in worry

Changes in IU precede changes in worry levels during therapy (Dugas & Ladouceur, 2000). Although not a direct assessment of whether IU is involved in the etiology of worry, this finding lends support to the idea that IU at least plays a maintenance role in pathological worrying. To examine whether IU has a causal influence on worry, Ladouceur, Gosselin and Dugas (2000) manipulated IU using a gambling procedure in which participants were motivated to win as much money as possible. One group of participants were told that their odds were better than a previous group’s odds (decreased IU) and another group of participants were told that their odds were worse than a previous group’s odds (increased IU). Those in the increased IU group reported higher levels of worry than those in the decreased IU group. However, the questions examining IU and worry were linked to the specific gambling task in question, and it is unclear whether this finding extends beyond this particular context.

Deschenes, Dugas, Radomsky and Buhr (2010) manipulated beliefs about IU by informing participants that uncertainty was helpful in solving problems (low IU) or that uncertainty was unhelpful in solving problems (high IU). They found that participants in the high IU group rated worry steps in a CI as significantly more likely than those in the low IU

2 _{De Bruin et al. (2007) found that, while IU predicted trait worry, there was little, if any association}

group. However, no difference was found in CI steps, but this is likely to be due to the experimental method differing from Davey’s (2006a) CI methodology. In Deschenes et al.’s (2010) methodology, participants were asked what they would be afraid of if their worry actually happened. This is more likely to make individuals examine whether their worry is actually likely to occur.

1.8.5 Intolerance of uncertainty validity and specificity

Buhr and Dugas (2006) examined the construct validity of IU. They found that worry was more related to IU than to intolerance of ambiguity. Additionally, IU was identified as a better predictor of worry than perfectionism and perceived control, and contributed unique variance not accounted for by these other cognitive factors. Carleton et al. (2007) argue that a dimensional structure underpins IU. Indeed, one of the criticisms of the current IU construct comes from Birrell et al. (2011) who note that current definitions of IU are categorical in nature. Birrell et al. (2011) suggest that two factors underlie IU, as measured by the Intolerance of Uncertainty Scale: (1) desire for predictability and active engagement in seeking certainty (which they argue represents an approach response to uncertainty), and (2) paralysis of cognition and action in the presence of uncertainty (which they claim is an avoidance response to uncertainty).

Questions surround the specificity of IU to worry, and it seems IU is a transdiagnostic characteristic. A number of studies have shown the high IU is present in samples with depression (e.g., Dugas, Schwartz, & Francis, 2004), and IU predicts OCD severity (Calleo, Hart, Björgvinsson, & Stanley, 2010). Nonetheless, some authors have demonstrated that IU is more closely related to worry than to other psychopathologies (Dugas et al. 2004).