A comparison of intolerance of uncertainty in analogue obsessive-compulsive disorder and generalized anxiety disorder☆
Introduction
Researchers have long been interested in the overlapping and distinguishing features of the anxiety and mood disorders (e.g., Brown, Chorpita, & Barlow, 1998; Clark & Watson, 1991; Fresco, Frankel, Mennin, Turk, & Heimberg, 2002). Among the anxiety disorders, much of this interest has focused on generalized anxiety disorder (GAD) and obsessive-compulsive disorder (OCD), primarily due to the apparent similarities in the cognitive processes associated with these disorders. Though research has consistently found worries and obsessions to be distinguishable in terms of content [e.g., real-life circumstances vs. unrealistic and magical thinking] (Brown, Moras, Zinbarg, & Barlow, 1993; Langlois, Freeston, & Ladouceur, 2000; Turner, Beidel, & Stanley, 1992), recent conceptualizations of GAD and OCD suggest that these two disorders may be fundamentally more similar in terms of the functionality of worry and compulsions (Comer, Kendall, Franklin, Hudson, & Pimentel, 2004). Similarly, both disorders, and more specifically worry and compulsions, may be related to intolerance of uncertainty.
Dugas, Gosselin, and Ladouceur (2001) have described intolerance of uncertainty as the excessive tendency of an individual to view the potential occurrence of future negative events as unacceptable, irrespective of the probability of their occurrence. Other researchers have offered similar definitions, describing intolerance of uncertainty as “beliefs about the necessity of being certain, about the capacity to cope with unpredictable change, and about adequate functioning in situations which are inherently ambiguous” (Obsessive Compulsive Cognitions Working Group, 1997, p. 678). Individuals who are intolerant of uncertainty, therefore, may believe that they lack sufficient coping or problem solving skills to effectively manage threatening situations that have the potential to evoke discomfort and negative emotionality.
Krohne (1993) suggests that anxious individuals engage in uncertainty-motivated behavior as a mechanism for coping with ambiguous and potentially threatening stimuli and to achieve an increased sense of control over potentially aversive situations. Inherent in this model is the suggestion that intolerance for uncertain negative events may be a driving force behind a number of behaviors and cognitions (e.g., worry, obsessions, compulsions, hypervigilance) associated with various anxiety disorders. That is, these behaviors and cognitions may serve as mechanisms by which one can attempt to avoid or control uncertain and potentially aversive situations. Recent research has begun to assess the link between intolerance of uncertainty and symptoms of both GAD and OCD, with preliminary evidence suggesting intolerance of uncertainty is highly related to both disorders (Dugas, Gagnon, Ladouceur, & Freeston, 1998; Steketee, Frost, & Cohen, 1998; Tolin, Abramowitz, Brigidi, & Foa, 2003).
Among individuals with GAD, it has been hypothesized that worry is an attempt to control the uncertainty associated with feared situations (Dugas, Buhr, & Ladouceur, 2004). That is, an individual who is intolerant of uncertainty may engage in worry to prepare for an uncertain negative event, consequently decreasing the anxiety (and potential surprise) associated with the feared situation. This conceptualization is consistent with the avoidance model of worry proposed by Borkovec (1994, also see Borkovec, Alcaine, & Behar, 2004), which suggests that worry may function as a means to avoid experiencing unwanted and/or aversive somatic arousal, images, thoughts, and emotions. Empirically, intolerance of uncertainty has been associated with measures of pathological worry and GAD (Dugas et al., 2001; Holaway, Mennin, Turk, & Heimberg, 2002), with some research suggesting that individuals with GAD may have a lower threshold for the experience of uncertainty than do non-clinical controls or individuals with other anxiety disorders (Ladouceur et al., 1999). Similarly, intolerance of uncertainty has been found to significantly distinguish both clinical (GAD) and non-clinical worriers from non-anxious controls (Buhr & Dugas, 2002; Holaway et al., 2002). Further, cognitive-behavioral therapies specifically focusing on features of intolerance of uncertainty have shown success in ameliorating worry and related symptoms in individuals with GAD (Dugas et al., 2003, Ladouceur et al., 2000).
Though intolerance of uncertainty has received much attention in the literature on GAD, until recently, it has been less studied in OCD. Theoretical descriptions of the construct as it relates to OCD, however, date back to the 1970s (e.g., Carr, 1974). It has been suggested that individuals with OCD possess an excessive need for certainty (Makhlouf-Norris & Norris, 1972) and may experience significant anxiety until certainty is obtained (Beech & Liddell, 1974; Kozak, Foa, & McCarthy, 1987). Specifically, it has been hypothesized that intolerance of uncertainty in OCD may be most related to compulsions and ritualistic behaviors (Beech & Lidell, 1974; Steketee et al., 1998, Tolin et al., 2003). That is, individuals may view rituals and compulsions as their only available strategy for reducing the distress associated with the possibility of a feared outcome. Steketee et al. (1998) found that individuals with OCD reported more intolerance of uncertainty than those with other anxiety disorders and normal controls. In addition, intolerance of uncertainty was the only construct (compared to responsibility, control, threat estimation, tolerance for anxiety, and coping) to successfully predict OCD symptoms above and beyond mood and worry. Tolin et al. (2003) found that patients with OCD did not report more intolerance of uncertainty than non-anxious controls; however a subset of OCD patients identified as compulsive checkers reported significantly more intolerance of uncertainty than OCD participants without a checking compulsion or non-anxious controls.
Few studies have directly examined the specificity of intolerance of uncertainty to particular psychological disorders (e.g., Dugas et al., 2001; Dugas, Marchand, & Ladouceur, 2005; Ladouceur et al., 1999). Though not the principal focus, existing studies that have compared intolerance of uncertainty in GAD to other disorders have done so primarily with OCD, with a few including comparisons with panic disorder. For example, using a non-clinical sample, Dugas et al. (2001) found that although intolerance of uncertainty was strongly correlated with both pathological worry and OCD symptoms, the relationship between intolerance of uncertainty and worry was significantly stronger than the relationship between intolerance of uncertainty and symptoms of either OCD or panic disorder. Further, although OCD symptoms were a significant predictor of intolerance of uncertainty, worry accounted for significant additional variance. In a recent examination by Dugas et al. (2005), patients with non-comorbid GAD were found to report significantly higher levels of intolerance of uncertainty than patients with a non-comorbid diagnosis of panic disorder with agoraphobia (PDA). Further analyses across both diagnostic groups found intolerance of uncertainty to be significantly correlated with worry but not significantly related to symptoms of PDA (i.e., fear of bodily sensations, agoraphobic cognitions). Similarly, Ladouceur et al. (1999) found intolerance of uncertainty to be greater among patients with GAD than in a mixed anxiety disorder group (73.7% of these patients had OCD). However, Steketee et al. (1998) reported contrasting results, finding that individuals with OCD reported greater intolerance of uncertainty than those in a mixed anxiety disorder group which included individuals with panic disorder [with and without agoraphobia] (49%), GAD (22.4%), social anxiety disorder (14.3%), and agoraphobia alone (14.3%). Differences in the findings of these two studies may be partially due to differences of measurement, as well as the lack of direct comparisons between individuals with GAD and OCD. Most recently, Sexton, Norton, Walker, and Norton (2003) tested a hierarchical model of vulnerabilities to anxiety in a college student sample; intolerance of uncertainty predicted worry and generalized anxiety symptoms but did not predict obsessive-compulsive, panic, or hypochondriacal symptoms. These results have since been replicated in a clinical sample (Norton, Sexton, Walker, & Norton, in press).
In summary, existing research suggests intolerance of uncertainty may be related to both OCD and GAD, with mixed findings regarding its specificity to either disorder. Further research directly comparing individuals with OCD and GAD on their report of intolerance of uncertainty is needed to better understand the specificity and generality of the construct.
The current study had three primary goals. First, we examined self-reported intolerance of uncertainty among individuals with analogue GAD, analogue OCD, non-anxious individuals, and individuals reporting elevated symptoms of both GAD and OCD, to determine if these groups differed significantly on this construct. Second, we examined whether intolerance of uncertainty was more strongly related to GAD or OCD symptoms, specifically testing the relationships among intolerance of uncertainty, worry, GAD, obsessions, and compulsions across the entire sample. Finally, we examined whether the relationship between intolerance of uncertainty and OCD symptoms would remain significant when worry and generalized anxiety were controlled, as well as whether the relationship between intolerance of uncertainty and worry and generalized anxiety would remain significant when controlling for OCD symptoms.
Section snippets
Participants and procedure
A sample of 560 undergraduate students at a large metropolitan university completed questionnaires pertaining to worry, GAD, OCD, and intolerance of uncertainty, as well as additional measures not related to the present study. Students received partial course credit for their participation. Five hundred and five students with complete data were included in the current study (69.2% women and 30.8% men, M age = 18.70 years, S.D. = 2.32). Of the 500 participants reporting ethnicity, 316 were
Preliminary analyses
Participants in the four diagnostic groups did not differ with respect to age [F(3, 260) = .312, P = .817]; however, the groups differed on gender ratio [χ2(3, N = 264) = 11.69, P < .01], as there were significantly more males in the OCD group (52.6%) than in either the GAD (18.2%) or GAD + OCD (23.7%) groups. An independent samples t-test, however, indicated that IUS scores did not differ as a function of gender [t(262) = −.471, P = .638]. Due to inadequate sample sizes, an examination of the equality of
Discussion
Intolerance of uncertainty has received increasing research attention in relation to GAD and OCD in the last few years. Most studies have found intolerance of uncertainty to be most related to GAD (e.g., Dugas et al., 2001, Ladouceur et al., 1999, Sexton et al., 2003), specifically to its hallmark symptom of pathological and uncontrollable worry, although a number of studies found support for a significant relationship between intolerance of uncertainty and symptoms of OCD (e.g., Steketee et
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Portions of this article were presented at the annual meeting of the Anxiety Disorders Association of America in Toronto, Canada, March 2003.