Intolerance of uncertainty and adult separation anxiety.

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Intolerance of Uncertainty and Adult Separation Anxiety a

b

Paul A. Boelen , Albert Reijntjes & R. Nicholas Carleton

c

a

Department of Clinical and Health Psychology, Utrecht University, Utrecht, The Netherlands b

Department of Child and Adolescent Studies, Utrecht University, Utrecht, The Netherlands c

Department of Psychology and the Anxiety and Illness Behaviours Laboratory, University of Regina, Regina, Canada Published online: 07 Mar 2014.

To cite this article: Paul A. Boelen, Albert Reijntjes & R. Nicholas Carleton (2014) Intolerance of Uncertainty and Adult Separation Anxiety, Cognitive Behaviour Therapy, 43:2, 133-144, DOI: 10.1080/16506073.2014.888755 To link to this article: http://dx.doi.org/10.1080/16506073.2014.888755

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Cognitive Behaviour Therapy, 2014 Vol. 43, No. 2, 133–144, http://dx.doi.org/10.1080/16506073.2014.888755

Intolerance of Uncertainty and Adult Separation Anxiety Paul A. Boelen1*, Albert Reijntjes2 and R. Nicholas Carleton3 1


Department of Clinical and Health Psychology, Utrecht University, Utrecht, The Netherlands; 2Department of Child and Adolescent Studies, Utrecht University, Utrecht, The Netherlands; 3Department of Psychology and the Anxiety and Illness Behaviours Laboratory, University of Regina, Regina, Canada Abstract. Intolerance of uncertainty (IU)—the tendency to react negatively to situations that are uncertain—is involved in different anxiety disorders and depression. No studies have yet examined the association between IU and symptoms of adult separation anxiety disorder. However, it is possible that greater difficulties tolerating uncertainties that can occur in relationships with attachment figures inflate fears and worries about the consequences of being separated from these attachment figures. The current study examined the possible role of IU in symptoms of adult separation anxiety disorder, relative to its role in symptoms of generalized anxiety disorder (GAD), obsessive compulsive disorder (OCD), social anxiety, and depression, using self-reported data from 215 undergraduates (92% women) with elevated separation anxiety. Findings showed that IU was significantly associated with symptom levels of separation anxiety disorder, GAD, OCD, social anxiety, and depression (rs. :30). IU continued to explain variance in OCD, social anxiety, and depression (but not GAD and separation anxiety) when controlling for the association of neuroticism, attachment anxiety, and attachment avoidance with these symptoms. Additional findings indicated that IU is more strongly associated with symptoms of GAD, OCD, and social anxiety than symptoms of adult separation anxiety disorder and depression. Key words: intolerance of uncertainty; adult separation anxiety disorder; anxiety; depression. Received 16 December 2013; Accepted 26 January 2014 Correspondence address: Paul A. Boelen, Department of Clinical and Health Psychology, Utrecht University, P.O. Box 80140, 3508 TC Utrecht, The Netherlands. Tel: þ 31 30 2533021. Fax: þ31 30 2534718. E-mail: [email protected]

Intolerance of uncertainty (IU) has been defined as “a cognitive bias that affects how a person perceives, interprets, and responds to uncertain situations on a cognitive, emotional, and behavioral level” (Dugas, Schwartz, & Francis, 2004, p. 835). People high in IU experience the possibility of negative future events occurring as distressing and believe that uncertainty is negative, reflects badly on a person, and should be avoided (cf. Koerner & Dugas, 2008). IU has been thought to be a specific vulnerability factor for worry and generalized anxiety disorder (GAD); however, there is increasingly robust evidence that IU is a transdiagnostic vulnerability factor associated with the development and maintenance of anxiety and depression symptoms (e.g., Carleton et al., 2012; Gentes & Ruscio, 2011). q 2014 Swedish Association for Behaviour Therapy

Specifically, there is evidence that, apart from its role in worry/GAD (Koerner & Dugas, 2008), IU is associated with panic disorder (Dugas, Gosselin, & Ladouceur, 2001), obsessive compulsive disorder (OCD; Holaway, Heimberg, & Coles, 2006), social anxiety (Boelen & Reijntjes, 2009a; Boelen, Vrinssen, & Van Tulder, 2010; Carleton, Collimore, & Asmundson, 2010), posttraumatic stress (Bardeen, Ferges, & Wu, 2013; Fetzner, Horswill, Boelen, & Carleton, 2013; White & Gumley, 2009), health anxiety (Boelen & Carleton, 2012), and depression (Carleton et al., 2012; Van der Heiden et al., 2010). The seemingly pervasive nature of IU across anxiety and depressive psychopathology supports its further exploration. To our knowledge, no studies have yet investigated the association of IU with


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symptoms of adult separation anxiety disorder. Adult separation anxiety disorder is characterized by exaggerated fears about separations from, and harm befalling, close attachment figures. The disorder was recently included in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013) and parallels childhood separation anxiety disorder as previously defined in DSM-IV with onset occurring after 18 years of age (APA, 2000; for reviews see Bo¨gels, Knappe, & Clark, 2013; Manicavasagar et al., 2010). It is conceivable that IU is associated with adult separation anxiety. That is, to some extent, uncertainty may be considered an intrinsic part of close attachment relationship (cf. Knobloch, 2008); for example, theoretically, there is always a possibility that some form of harm will befall an attachment figure. Likewise, to a greater or lesser extent, people may experience uncertainty about how they will function in the (temporal or definite) absence of a close attachment figure. It seems plausible that increased difficulties to tolerate such uncertainties may inflate fears and worries about the consequences of being separated from close attachment figures and fuel proximity seeking behavior that serves to reduce these uncertainties, fears, and worries. Indeed, there is evidence that children with separation anxiety disorder have difficulties with ambiguous situations (Bo¨gels & Zigterman, 2000), which may result from IU. The present study was designed to explore the possibility of a relationship between IU and adult separation anxiety disorder, using data from students with elevated symptom levels of adult separation anxiety disorder. This was deemed relevant for a number of reasons. First, we felt it was relevant to examine the extent to which prior findings of a significant association between IU and different anxiety disorders generalized across symptoms typical of adult separation anxiety. Secondly, there is little knowledge about psychological processes underlying the development and maintenance of adult separation anxiety disorder symptoms and enhancing this knowledge is important for the development of treatment methods for adult separation anxiety (Bo¨gels et al., 2013). If IU would be found to be involved in adult separation anxiety, this could imply that established treatment interventions for reducing IU (e.g.,

COGNITIVE BEHAVIOUR THERAPY

exposure to uncertainty, improving problemsolving skills; Dugas & Ladouceur, 2000) are possibly effective for reducing adult separation anxiety. This study had four interrelated aims. As the first aim, we examined the associations between IU and symptom levels of adult separation anxiety disorder, and compared these associations with the relationships between IU and symptom levels of GAD, OCD, social anxiety, and depression. Several factor analytic studies suggest that IU includes two distinguishable yet correlated dimensions of Prospective IU and Inhibitory IU (e.g., Carleton, Norton, & Asmundson, 2007; McEvoy & Mahoney, 2011). Prospective IU refers to cognitive perceptions of threat pertaining to future uncertainty (tapped with items including “Unforeseen events upset me greatly”), whereas Inhibitory IU refers to behavioral symptoms indicating apprehension due to uncertainty (e.g., “The smallest doubt can stop me from acting”). Accordingly, in this study, we also focused on these two dimensions of IU. Secondly, we examined the degree to which IU and its two dimensions were related to symptom levels of adult separation anxiety disorder and these other disorders, when taking into account neuroticism and attachment insecurity. There is strong evidence that these two personality variables are associated with anxiety and depression; for instance, neuroticism is a common feature of anxiety and depression (Weinstock & Whisman, 2006) and several studies have shown that attachment insecurity is linked with greater propensity to anxiety and depression (Mickelson, Kessler, & Shaver, 1997; Myhr, Sookman, & Pinard, 2004; Van IJzendoorn & Bakermans-Kranenburg, 1996). Both personality variables have also been implicated in IU (cf. Dugas, Buhr, & Ladouceur, 2003; Hirsh & Inzlicht, 2008; Norton, Sexton, Walker, & Norton, 2005). To enhance knowledge on the potential contribution of IU to separation anxiety disorder, GAD, OCD, social anxiety, and depression beyond these established correlates of these symptoms, we explored the linkage of IU with these symptoms taking into account individual variations in neuroticism and attachment insecurity. Individual differences in attachment insecurity were measured along two dimensions of attachment anxiety (i.e., a person’s predisposition toward anxiety and


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IU and Adult Separation Anxiety

vigilance about rejection and abandonment), and attachment avoidance (i.e., a person’s discomfort with closeness and dependency or a reluctance to be intimate with others). There is recent evidence that IU may interact with other cognitive processes in producing maladaptive responses, including worry (Ruggiero et al., 2012). Accordingly, it was deemed relevant to explore whether IU interacted with the personality-variables assessed in this study (i.e., neuroticism, attachment anxiety, and attachment avoidance). For instance, it could be possible that neuroticism inflates the impact of IU on emotional distress (cf. Hirsh & Inzlicht, 2008) or that attachment anxiety and IU interacted in contributing to adult separation anxiety (cf. Bo¨gels et al., 2013). Accordingly, the third aim was to examine the possibility that IU interacted with neuroticism, attachment anxiety, and attachment avoidance in contributing to the explained variance in symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression. Fourthly and finally, to enhance our understanding of the specificity versus generality of IU to different emotional disorders, we examined the specificity of IU to symptom levels of adult separation anxiety, GAD, OCD, social anxiety, and depression, when taking into account the shared variance between these different symptom -clusters.

Methods Participants and procedure We used data from 215 students from Utrecht University, who all had a score of $ 16 on the Adult Separation Anxiety Symptom Questionnaire (ASA-27), described below. This $ 16 score is a cutoff score for adult separation disorder “caseness” recommended by Manicavasager, Silove, Wagner, and Droby (2003) based on sensitivity and specificity analyses; in their study, Manicavasager et al. (2003) found this cutoff score to yield a sensitivity of 97% for a diagnosis of adult separation anxiety based on a clinical interview. The current participants were selected from a group of 805 students who all participated in an ongoing internet-based research program based in the Department of Clinical and Health Psychology of Utrecht University that focuses on the role of cognitive

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behavioral variables in anxious and depressive symptoms. Participants for this research program were recruited via posters in university buildings and announcements on the university Internet site. All participants participated in return for course credits. The mean age of the N ¼ 215 participants included in the current study was 21.6 (SD ¼ 2.0) years, most of them (n ¼ 198; 92.1%) were female, and most of them (n ¼ 146, 67.9%) were currently involved in a romantic relationship. We compared these three sociodemographic variables between participants with scores of $16 on the ASA-27, who were selected for this study (N ¼ 215), and the other participants from the research program with ,16 scores on the ASA-27 (N ¼ 590) not selected for this study. The former group, selected for this study, was slightly younger (M ¼ 21.6 vs. M ¼ 22.1; t(782.89) ¼ 2.03, p , .001), included relatively more women (92.1% vs. 81.0%; Fisher exact test p , .001), and included relatively more people having a romantic relationship (67.9% vs. 59.2%; Fisher exact test p , .05).

Measures Intolerance of Uncertainty Scale Short Form (IUS-12). The IUS-12 developed by Carleton et al. (2007), Dutch version Boelen et al. (2010), Helsen, Van den Bussche, Vlaeyen, and Goubert (2013), is a 12-item measure of IU. It has two factors, tapping Prospective IU (seven-item subscale; e.g., “I can’t stand being taken by surprise”) and Inhibitory IU (fiveitem subscale; e.g., “When it’s time to act, uncertainty paralyses me”), respectively (Carleton et al., 2007; McEvoy & Mahoney, 2011). Items are scored on five-point scales (1 ¼ not at all characteristic of me; 5 ¼ entirely characteristic of me). The IUS-12 has yielded excellent psychometric properties in clinical and non-clinical samples (e.g., Carleton et al., 2007). In the present sample, the a values of the IUS-12 total scale was .87, of Prospective IU was .87, and of Inhibitory IU was .79. Adult Separation Anxiety Symptom Questionnaire (ASA-27). The ASA-27, developed by Manicavasager, Silove, Wagner, and Droby (2003) is a 27-item measure tapping different symptoms of adults separation anxiety, including those included in the symptom-criteria listed in DSM-IV (APA, 2000). The items (e.g., “Have you been worrying a lot about people you care


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about leaving you?”; “Have you tried to avoid being at home alone especially when people close to you are out?”) are each rated on a four-point scale (0 ¼ this never happens; 3 ¼ this happens all the time). The English (Manicavasager et al., 2003) and Dutch (Boelen, 2013) versions have yielded adequate psychometric properties. Cronbach’s a in the present sample was .80. Beck Depression Inventory (BDI). The BDI is a commonly used measure of depression. It contains 21 groups of four statements representing depressive symptoms at increasing levels of severity. The English (Beck, Steer, & Brown, 1996) and Dutch versions of the BDI (Van der Does, 2002) have adequate psychometric properties. The a in this sample was :90: Generalized Anxiety Disorder Questionnaire for DSM-IV (GAD-Q-IV). The GAD-Q-IV (Dutch version Boelen & Reijntjes, 2009a; Newman et al., 2002) is a nine-item measure of GAD as defined in DSM-IV (APA, 2000). The items (e.g., “Do you experience excessive worry?”) assess the occurrence of worry, worry topics, somatic symptoms related to GAD, and distress and disability linked with the worry. It can be used as dichotomous measure of GAD “caseness” and to obtain a continuous score of GAD severity. In the current study, this latter scoring format was used. The a in this sample was .83. Obsessive Compulsive Inventory revised version (OCI-R). The OCI-R is an 18-item measure of OCD symptoms (Foa et al., 2002). The items (e. g., “I check things more often than necessary”) are rated on five-point scales (0 ¼ not at all; 4 ¼ extremely). The OCI-R consists of six subscales (e.g., washing and checking) and its total score (used in the present study) provides a general index of OCD severity. English (Foa et al., 2002) and Dutch versions (Boelen & Reijntjes, 2009a) have yielded adequate psychometric properties. The a in this sample was .89. Social Phobia Inventory (SPIN). The SPIN is a 17-item questionnaire constructed by Connor et al. (2000) for the assessment of the fear, avoidance, and physiological symptoms that characterize social phobia. Respondents rate the presence of symptoms in the preceding week, on five-point scales (0 ¼ not at all, 4 ¼ extremely). Items (e.g., “Being criticized scares me a lot”) are summed to form an overall social anxiety severity score. The SPIN total score has good psychometric properties (Boelen & Reijntjes, 2009a; Connor et al., 2000). In this sample, the a was .91.


Experiences in Close Relationships Questionnaire, revised form (ECR-R). The shortened version of the ECR-R, originally developed by Fraley, Waller, and Brennan (2000), was used to measure the dimensions of attachment anxiety and attachment avoidance. Attachment anxiety was tapped by its five-item subscales (e.g., “I often worry that my partner will not want to stay with me”; a ¼ .87) and attachment avoidance by its six-item subscale (e.g., “I get uncomfortable when a romantic partner wants to get very close,” a ¼ .86). Respondents rate their agreement with statements on seven-point scales (0 ¼ strongly disagree, 6 ¼ strongly agree). Psychometric properties of the English (Fraley et al., 2000) and Dutch version (Boelen & Reijntjes, 2009b) are adequate. Shortened Eysenck Personality Questionnaire Neuroticism subscale (EPQ-N). This measure includes 12 items tapping neuroticism. Respondents indicate their agreement with items, using a forced-choice dichotomous response format (yes/no). English (Eysenck, Eysenck, & Barrett, 1985) and Dutch versions (Sanderman, Arrindell, Ranchor, Eysenck, & Eysenck, 1995) have good psychometric properties. The a in this sample was .77.

Results Preliminary analyses In order to examine whether prior findings that IU constitutes distinct dimensions of Prospective IU and Inhibitory IU (see Carleton et al., 2007) also applied to the current sample, we conducted confirmatory factor analysis using Amos (Arbuckle, 2003) to examine the factor structure of the IUS-12. Specifically, we compared the fit of a unitary model with the fit of a two-factor model with symptoms constituting distinct factors of Inhibitory IU and Prospective IU. Outcomes showed that the two-factor model fits the data well (Tucker-Lewis Index [TLI] ¼ .92, Comparative Fit Index [CFI] ¼ .93, Root Mean Square Error of Approximation [RMSEA] ¼ .075; Akaiki’s Information Criterion [AIC] ¼ 166.47) and fits better than the onefactor model (Tucker-Lewis Index [TLI] ¼ .74, CFI ¼ .79, RMSEA ¼ .132; AIC ¼ 303.31). Scores on the ASA-27 and BDI were slightly positively skewed and log-transformed in all of the analyses reported below. None of the other variables assessed demonstrated unacceptable


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levels of skew or kurtosis (i.e., none had positive standardized skewness values that exceeded 2 or positive standardized kurtosis values that exceeded 7; e.g., Tabachnick & Fidell, 2007). We examined whether scores on the variables assessed varied as a function of age, gender, and relationship status. Age was positively associated with GAD-Q-IV scores (r ¼ .14; p , .05). In addition, women reported higher scores on the SPIN, tapping social phobia (M ¼ 33.9 vs. M ¼ 28.5, t(21.4) ¼ 2.50, p , .05), and the EPQ-N, tapping neuroticism (M ¼ 7.3 vs. M ¼ 5.5, t(213) ¼ 2.54, p , .05). Finally, those who were currently not involved in a romantic relationship had higher levels of attachment anxiety (M ¼ 21.7 vs. M ¼ 17.1, t (213) ¼ 4.56, p , .001) and higher levels of attachment avoidance (M ¼ 18.3 vs. M ¼ 13.0, t(213) ¼ 5.60, p , .001) relative to those who were currently involved in such a relationship. As noted earlier, all participants included in this study had a $ 16 score on the ASA-27, and thus suffered clinical levels of adult separation anxiety (see Manicavasagar et al., 2003). To further characterize distress levels in our sample, we compared scores on the symptom measures with other student groups. Our sample had higher GAD-Q-IV scores relative to students examined by Holaway et al. (2006); M ¼ 6.82 vs. M ¼ 3.87, t (214) ¼ 14.94, p , .001; similar OCI-R scores relative to students examined by Hajcak, Huppert, Simons, and Foa (2004); M ¼ 11.94 vs. M ¼ 11.95, t , 1; similar SPIN scores relative to 192 students in the study of Radomsky et al. (2006); M ¼ 16.56 vs. M ¼ 17.5, t(214) ¼ 1.22, p ¼ .22; and similar BDI scores relative to the student sample studied by Helsen et al. (2013); M ¼ 10.88 vs. M ¼ 10.44, t , 1. The mean IUS-12 total score of participants was 34.3 (SD ¼ 7.9), the mean Prospective IU score was 21.3 (SD ¼ 5.5), and the mean Inhibitory IU was score was 13.1 (SD ¼ 3.7).

Associations between IU and symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression Table 1 shows zero-order correlations of the IUS-12 total score and the two dimensions of IU with each of the symptom measures.

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Table 1. Correlations of IU with symptom measures

ASA-27 GAD-Q-IV OCI-R SPIN BDI

IUS-12 total score

Prospective IU

Inhibitory IU

.31 .49 .39 .58 .43

.24 .37 .34 .39 .30

.30 .49 .27 .67 .47

Notes. All correlations were statistically significant at p , .001. ASA-27, Adult Separation Anxiety Symptom Questionnaire; BDI, Beck Depression Inventory; GAD-Q-IV, Generalized Anxiety Disorder Questionnaire for DSM-IV; OCI-R, Revised Obsessive Compulsive Inventory; SPIN, Social Phobia Inventory.

Correlations were all positive and statistically significant, even at a Bonferroni-corrected plevel (.05/15) of .003. Importantly, the IUS-12 total scale and subscale scores all correlated significantly with the ASA-27 scores.

Associations of IU with symptoms beyond neuroticism, attachment anxiety, and attachment avoidance Next, we evaluated the extent to which both dimensions of Inhibitory IU and Prospective IU explained variance in symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression, when controlling for the shared variance between these IU dimensions as well as for the variance explained by neuroticism (assessed with the EPQ-N) and the dimensions of attachment anxiety and attachment avoidance (assessed with the ECR-R). To this end, five linear regression analyses were conducted with symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression, respectively, as dependent variables. Neuroticism, attachment anxiety, attachment avoidance, Inhibitory IU, and Prospective IU were entered as independent variables. Table 2 summarizes the regression models; the first three columns display the Bs, SEs, and bs of the five independent variables when these were entered to the regression models simultaneously. The fourth column shows the DR 2 for each variable when entered as a first step to the equation and thus represents the percentage of variance in the dependent variable explained by this indepen-

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Table 2. Summary of regression analyses predicting symptom scores


B

DR 2 when entered as first step

DR 2 when entered as last step

.234** .272*** .063 .078 .030

.138*** .142*** .046** .060*** .090***

.029** .059*** .003 .004 ,.001

.624*** 2.005 .090 .042 .050

.470*** .047** .033** .139*** .242***

.205*** ,.001 .006 .001 .001

.173* 2.001 .231** .251** 2.020

.096*** .027* .071*** .119*** .075***

.016* ,.001 .042** .046** ,.001

b

SE B

DV ¼ Adult Separation Anxiety (ASA-27) Neuroticism .011 .004 Attachment anxiety .005 .001 Attachment avoidance .001 .001 Prospective IU .002 .002 Inhibitory IU .001 .003 DV ¼ Generalized Anxiety (GAD-Q-IV) Neuroticism .620 .068 Attachment anxiety 2 .002 .022 Attachment avoidance .038 .024 Prospective IU .022 .031 Inhibitory IU .039 .054 DV ¼ Obsessive Compulsiveness (OCI-R) Neuroticism .586 .290 Attachment anxiety 2 .002 .095 Attachment avoidance .332 .100 Prospective IU .452 .131 Inhibitory IU 2 .052 .231 DV ¼ Social Anxiety (SPIN) Neuroticism .763 .260 Attachment anxiety .165 .086 Attachment avoidance .157 .090 Prospective IU .126 .118 Inhibitory IU 1.408 .207 DV ¼ Depression (BDI) Neuroticism .013 .003 Attachment anxiety .002 .001 Attachment avoidance .001 .001 Prospective IU .000 .001 Inhibitory IU .005 .002

.197** .105 .096 .061 .460***

.313*** .101*** .090*** .152*** .446***

.020** .009 .007 .003 .110***

.372*** .165** .049 .022 .189*

.306*** .111*** .046** .098*** .242***

.073*** .022** .002 ,.001 .019*

Notes. ASA-27, Adult Separation Anxiety Symptom Questionnaire; BDI, Beck Depression Inventory; DV, dependent variable; IU, intolerance of uncertainty; GAD-Q-IV, Generalized Anxiety Disorder Questionnaire for DSM-IV; OCI-R, Revised Obsessive Compulsive Inventory; SPIN, Social Phobia Inventory. *p , .05, **p , .01, and ***p , .001.

dent variable, when not taking into account the variance explained by the other variables in the equation. The fifth column shows the DR 2 for each variable when entered as a last step to the equation and thus represents the percentage of variance in the dependent variable explained by this independent variable, after controlling for the variance explained by the other independent variables in the equation. The regression model predicting adult separation anxiety disorder was statistically significant (R 2 ¼ .23, f 2 ¼ .26, F(5, 214) ¼ 12.55, p , .001), with neuroticism and attachment anxiety (but not attachment avoidance, Prospective IU, and Inhibitory IU)

explaining a unique proportion of variance in separation anxiety scores. The regression model predicting GAD scores was also f 2 ¼ .92, F(5, significant (R 2 ¼ .48, 214) ¼ 39.12, p , .001); neuroticism was the single independent variable explaining unique variance. The regression model predicting OCD scores was statistically significant as well (R 2 ¼ .20, f 2 ¼ .25, F(5, 214) ¼ 10.19, p , .001); neuroticism, attachment avoidance, and, most pertinent to the current study aims, Prospective IU explained unique variance. The regression model predicting social anxiety scores was also statistically significant (R 2 ¼ .50, f 2 ¼ 1.0, F(5, 214) ¼ 42.36, p , .001). Neuroticism and Inhibitory IU


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explained a unique proportion of variance. Finally, the regression model predicting depression severity was statistically significant (R 2 ¼ .37, f 2 ¼ .59, F(5, 214) ¼ 24.68, p ¼ .001); neuroticism, attachment anxiety, and Inhibitory IU explained unique variance. Further analyses were performed with the IUS-12 total score entered to the regression models instead of the Inhibitory IU and Prospective IU subscales. The IUS-12 total score accounted for statistically significant and unique variance beyond neuroticism (EPQ-N) and attachment anxiety and attachment avoidance (ECR-R) in OCI-R scores (b ¼ .25, p , .01) and SPIN scores (b ¼ .35, p , .001), but not ASA-27 scores (b ¼ .10, p ¼ .21), GAD-Q-IV scores (b ¼ .07, p ¼ .25), and BDI scores (b ¼ .14, p ¼ .054).

Additional analyses with interactions between IU and neuroticism, attachment anxiety, and attachment avoidance We conducted additional analyses to examine whether the associations of Inhibitory IU and Prospective IU with the symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression (reported in the previous subsection and Table 2) were qualified by neuroticism, attachment anxiety, and attachment avoidance. Specifically, we conducted all the analyses reported in the previous subsection again, now adding an extra step to each regression equation in which the following six interaction terms were included: (i) Inhibitory IU £ attachment anxiety; (ii) Inhibitory IU £ attachment avoidance; (iii) Inhibitory IU £ neuroticism; (iv) Prospective IU £ attachment anxiety; (v) Prospective IU £ attachment avoidance; and (vi) Prospective IU £ neuroticism. In these analyses, independent variables were centered to reduce multi-collinearity (cf. Aiken & West, 1991). Outcomes showed that adding this extra block with interaction terms to the regression equation with adult separation anxiety as dependent variable added a significant amount of variance to the variance explained by the model; DR 2 ¼ .05, DF(6, 203) ¼ 2.57, p , .05. However, none of the interaction terms explained unique variance (bs , .12, ps . .14). Adding this extra block to the


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regression equation did not explain additional variance in GAD scores, OCI scores, or depression scores (all DFs , 1). However, adding this extra block did explain additional variance in SPIN scores (DR 2 ¼ 3%; DF (6, 203) ¼ 2.17, p , .05), with findings pointing at a significant interaction between Prospective IU £ attachment avoidance (b ¼ .15, p , .05), beyond the main effects of neuroticism (b ¼ .20, p , .05) and Inhibitory IU (b ¼ .45, p , .001) reported in our previous subsection (and Table 2). Simple slope analysis (Aiken & West, 1991) showed that, at high levels of attachment avoidance (i.e., 1 SD above the mean), Prospective IU was positively correlated with social anxiety severity (b ¼ .19, p , .05), whereas, at low levels of attachment avoidance (i.e., 1 SD below the mean), Prospective IU was not significantly correlated with social anxiety severity (b ¼ 2.08, p ¼ .35).

Additional analyses with sociodemographic variables In a further series of regression analyses, we examined whether findings changed when we controlled for gender, age, and relationship status. To this end, the regression equations from the previous subsection were taken as a starting point, and we added one extra block of independent variables to the five regression equations, including gender, age, relation status, and the interaction terms of these three variables with Prospective IU and Inhibitory IU. Adding this extra block did not explain a statistically significant amount of additional variance in symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression (all DR 2s , .05, all DFs , 1.19, all ps . .30).

Specificity of IU to symptom levels of adult separation anxiety disorder, GAD, OCD, social anxiety, and depression To further examine the degree to which IU was specifically associated with adult separation anxiety disorder, GAD, OCD, social anxiety, and depression, a regression analysis was conducted with the IUS total score as the dependent variable and scores on the five symptom measures as independent variables that were entered into the regression equation simultaneously. Outcomes of this regression


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analysis are summarized in Table 3. The model was significant; R 2 ¼ .43, f 2 ¼ .75, F(5, 214) ¼ 31.13, p , .001. Symptom levels of GAD, OCD, and social anxiety, but not symptom levels of adult separation anxiety and depression, explained a unique proportion of the variance in IUS-12 total scores. Similar analyses were done with Inhibitory IU and Prospective IU as dependent variables (see Table 3). The model predicting Inhibitory IU was significant; R 2 ¼ :51, f 2 ¼ 1.04, F(5, 214) ¼ 43.38, p , .001, with GAD and social anxiety levels explaining unique proportions of variance. The model predicting Prospective IU was also significant; R 2 ¼ .24, f 2 ¼ .32, F(5, 214) ¼ 12.82, p , .001; symptom levels of GAD, OCD, and social anxiety explained unique proportions of variance in Prospective IU. Variance inflation factors (1.57– 2.17) did not point at problematic collinearity in any of the regressions reported in Table 3.

Discussion To our knowledge, this is the first study to investigate the linkage between IU and symptoms of adult separation anxiety dis-

order. As noted, it seems plausible that fears and worries associated with uncertainty experienced in relationships with attachment figures may spiral into debilitating anxiety about separations from, and harm befalling these figures, once this uncertainty is not well tolerated. Some of the current findings were in line with this notion. That is, zero-order correlations (Table 1) showed that generic IU, indexed by the IUS-12 total score, as well as its dimensions of Prospective IU and Inhibitory IU, were significantly associated with symptom levels of adult separation anxiety disorder. In addition, IU and its dimensions were significantly associated with symptom levels of GAD, OCD, social anxiety, and depression. As such, the present findings among those with clinical level of adult separation anxiety symptoms accord with prior evidence that IU is a transdiagnostic correlate of different forms of anxiety and depressive psychopathology (e.g., Carleton et al., 2012; Gentes & Ruscio, 2011); the present findings complement prior research by showing that IU is also correlated with symptom levels of adult separation anxiety disorder.

Table 3. Summary of regression analyses predicting intolerance of uncertainty

B

SE B

b

DV ¼ IUS-12 total score Adult Separation Anxiety (ASA-27) 24.295 3.726 2 .074 Generalized Anxiety (GAD-Q-IV) .759 .189 .278*** Obsessive Compulsiveness (OCI-R) .103 .049 .128* Social Anxiety (SPIN) .300 .047 .428*** Depression (BDI) 2.911 5.450 .039 DV ¼ Inhibitory IU Adult Separation Anxiety (ASA-27) 22.174 1.609 2 .081 Generalized Anxiety (GAD-Q-IV) .328 .082 .257*** Obsessive Compulsiveness (OCI-R) 2.008 .021 2 .022 Social Anxiety (SPIN) .187 .020 .572*** Depression (BDI) 2.195 2.353 .063 DV ¼ Prospective IU Adult Separation Anxiety (ASA-27) 22.121 2.990 2 .053 Generalized Anxiety (GAD-Q-IV) .432 .152 .228** Obsessive Compulsiveness (OCI-R) .110 .039 .198** Social Anxiety (SPIN) .112 .038 .231** Depression (BDI) .699 4.374 .013

DR 2 when entered DR 2 when entered as first step as last step .096*** .239*** .292*** .340*** .200

.004 .044*** .012* .112*** .001

.090*** .242*** .075*** .446*** .242***

.004 .038*** , .001 .201*** .002

.060*** .139*** .206*** .152*** .098

.002 .030** .029** .033** , .001

Notes. ASA-27, Adult Separation Anxiety Symptom Questionnaire. BDI, Beck Depression Inventory. DV, dependent variable; IU, intolerance of uncertainty; GAD-Q-IV, Generalized Anxiety Disorder Questionnaire for DSM-IV; OCI-R, Revised Obsessive Compulsive Inventory; SPIN, Social Phobia Inventory. *p , .05, **p , .01, and ***p , .001.


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We also examined whether Prospective and Inhibitory IU continued to explain variance in symptoms assessed when controlling for the shared variance between these IU dimensions, as well as for the influence of neuroticism, attachment anxiety, and attachment avoidance. Notably, neither Inhibitory IU nor Prospective IU explained variance in symptom levels of adult separation anxiety disorder when controlling for these three variables, whereas both neuroticism and attachment anxiety did explain unique proportions of variance in separation anxiety levels. This finding suggests that IU does not account for individual variation in adult separation anxiety, beyond the variation that is explained by the general vulnerability to experience elevated distress, implicated in heightened neuroticism, and the predisposition toward anxiety and vigilance about rejection and abandonment, implicated in elevated attachment anxiety. Analyses also showed that IU and its components were unrelated to GAD severity, after accounting for neuroticism, attachment anxiety, and attachment avoidance. These results contrast the notion that IU is critical to GAD (e.g., Nelson & Shankman, 2011). Differences between the present and prior findings may be due to the fact that we used a self-report measure tapping a wide range of GAD symptoms, whereas several prior studies on IU and GAD only measured worry (e.g., Dugas et al., 2001). Differences may also be because our analyses were based on participants with elevated separation anxiety, whereas prior studies on IU and GAD relied on other samples (e.g., students with a wider range of distress, used in the study from Dugas et al. 2001; a clinical sample used in the study by Mahoney and McEvoy 2012). In the regression analyses predicting symptom levels of OCD, social anxiety, and depression, respectively, we found that Prospective IU explained unique variance in OCD severity, whereas Inhibitory IU explained unique variance in social anxiety and depression levels. These findings accord with prior evidence that Inhibitory IU is relatively more important to social phobia and depression symptoms, while Prospective IU is more specific to OCD (e.g., Carleton et al., 2012). Taking into account recent evidence that IU interacts with other variables in predicting


141

distress (Ruggiero et al., 2012), we explored whether the associations of IU with symptoms were qualified by neuroticism, attachment anxiety, and attachment avoidance. However, no such interaction effects were found in the regressions predicting symptom levels of adult separation anxiety, GAD, OCD, or depression. We did find evidence that Prospective IU interacted with attachment avoidance in explaining variance in social anxiety symptoms with Prospective IU being associated with elevated social anxiety at high but not low levels of attachment avoidance. There is some evidence for a linkage between attachment insecurity and social anxiety (Eng, Heimberg, Hart, Schneier, & Liebowitz, 2001); the present findings suggest that this association may be qualified by IU, specifically intolerance related to the prospect of future uncertainty. We did not find evidence that gender, age, or relationship status exerted an impact on the linkage between IU and the symptom levels we assessed. Further regression analyses were conducted to explore the specificity of IU (and its two dimensions) to symptom levels of adult separation anxiety, GAD, OCD, social anxiety, and depression in more detail. Outcomes showed that symptom levels of GAD, OCD, and social anxiety remained unique correlates of generic IU (IUS-12 total score) and Prospective IU after controlling for the shared variance among the symptom clusters. In addition, symptom levels of GAD and social anxiety emerged as unique correlates of Inhibitory IU. Generally, these findings accord with earlier findings that IU is a broad vulnerability factor for different anxious disorders (e.g., Norton et al., 2005; Sexton, Norton, Walker, & Norton, 2003). Yet, findings do raise some questions about the relative importance of Prospective IU and Inhibitory IU. There is some evidence that Inhibitory IU is a stronger correlate of depression and anxiety compared with Prospective IU; for instance, Fetzner et al. (2013) found Inhibitory IU to be a stronger correlate of posttraumatic stress, whereas Mahoney and McEvoy (2012) found Inhibitory IU to be a stronger correlate of social phobia, GAD, and depression. These findings suggest that the linkage of general IU with emotional distress is primarily driven by Inhibitory, not Prospective IU. Yet, our findings are not consistent with


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this picture. This suggests that future research should continue to explore the relative importance of the two dimensions of IU. This study has several limitations that provide directions for future research. First, the cross-sectional design does not allow for any conclusions to be drawn about the possible causal relationship between IU and symptoms assessed. Future research should consider assessing these relationships using Prospective designs. Second, the sample was composed of self-selected, highly educated, young people, most of whom were women. This limits the generalizability of the results. Notable too is that our reliance on a sample with clinical levels of adult separation anxiety disorder likely affected the current outcomes. For example, the associations between IU and symptom levels of GAD, OCD, social anxiety, and depression may be different in samples that include individuals with lower levels of adult separation anxiety. Likewise, the failure of IU to predict adult separation anxiety symptoms when controlling for neuroticism and attachment anxiety and avoidance may be due to the truncated range of separation anxiety scores; this result may be different when considering a wider range of separation anxiety symptoms. Third, our reliance on self-report measures to tap dependent and independent variables may have inflated correlations because of shared method variance. Future research should consider utilizing other (e.g., interview based) methods to assess variables. Notwithstanding these limitations, the current study adds to prior research in showing that IU and its components of Prospective IU and Inhibitory IU are associated with symptom levels of adults separation anxiety, but do not appear to contribute to individual differences in adults separation anxiety beyond personality variables of neuroticism and attachment anxiety. More broadly, the present findings complement earlier findings in showing that elevated IU renders a person prone to experience other anxiety symptoms and depression (Carleton et al., 2012; Norton et al., 2005; Sexton et al., 2003). Given the preliminary nature of the current results, it would be relevant for future studies to further explore this linkage. This is particularly important given that adult separation anxiety disorder was recently newly included in DSM5 (APA, 2013) and there is as of yet a paucity


of research about adequate treatments for this condition (Bo¨gels et al., 2013). Future research may identify IU as a vulnerability factor for adult separation anxiety disorder. If so, this would suggest that directly targeting IU by using specific cognitive behavioral interventions such as problem orientation training and exposure to uncertainty (e.g., Dugas & Ladouceur, 2000) could be beneficial in the treatment of this condition.

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Intolerance of uncertainty mediates the relation between generalized anxiety disorder symptoms and anger.

Anxiety sensitivity and intolerance of uncertainty as potential risk factors for cyberchondria.

Distress tolerance in OCD and anxiety disorders, and its relationship with anxiety sensitivity and intolerance of uncertainty.

Clarifying the unique associations among intolerance of uncertainty, anxiety, and depression.

How is the Beads Task related to intolerance of uncertainty in anxiety disorders?

Childhood separation anxiety and the pathogenesis and treatment of adult anxiety.

Adult separation anxiety disorder: accepted but little understood.

The interplay between sensory processing abnormalities, intolerance of uncertainty, anxiety and restricted and repetitive behaviours in autism spectrum disorder.

Environmental transmission of generalized anxiety disorder from parents to children: worries, experiential avoidance, and intolerance of uncertainty.

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

Intolerance of uncertainty as a framework for understanding anxiety in children and adolescents with autism spectrum disorders.

Intolerance of Uncertainty and Coping Mechanisms in Nonclinical Young Subjects.

Predicting intolerance of uncertainty in individuals with eating disorder symptoms.

Further clarifying prospective and inhibitory intolerance of uncertainty: Factorial and construct validity of test scores from the Intolerance of Uncertainty Scale.

Intolerance of Uncertainty: A Temporary Experimental Induction Procedure.

Adult separation anxiety and TCI-R personality dimensions in patients with anxiety, alcohol use, and gambling: a preliminary report.

The relationships among separation anxiety disorder, adult attachment style and agoraphobia in patients with panic disorder.

Assessment of co-morbidity of adult separation anxiety in patients with bipolar disorder.

Anxiety sensitivity and intolerance of uncertainty as potential risk factors for cyberchondria: A replication and extension examining dimensions of each construct.

The Relationship between Alexithymia and Intolerance of Uncertainty in Anorexia Nervosa.

Domain-specific intolerance of uncertainty in socially anxious and contamination-focused obsessive-compulsive individuals.

The relationship between intolerance of uncertainty in chiropractic students and their treatment intervention choices.

Intolerance of uncertainty, cognitive complaints, and cancer-related distress in prostate cancer survivors.

A Single Bout of Aerobic Exercise Reduces Anxiety Sensitivity But Not Intolerance of Uncertainty or Distress Tolerance: A Randomized Controlled Trial.