2.2. Measures
Intolerance of Uncertainty Scale (IUS-12) (26): This self-report instrument measures negative beliefs about uncertainty (27). IUS-12 has two subscales: prospective IU and inhibitory IU. Items are rated on a 5-point Likert scale from not at all characteristic of me (1) to entirely characteristic of me (5). The IUS-12 had excellent internal consistency (.91) and strong psychometric properties (28). The test-retest reliability and alpha coefficients of the scale were .76 and .88, respectively, for Iranian sample (29). In current study, Internal consistencies of IUS-12 was .84.
Disorder-Specific Intolerance of Uncertainty Scale (DSIU) (30): DSIU consists of eight three-item subscales measuring disorder-specific IU including generalized anxiety disorder (IU-GAD), social anxiety disorder (IU-SAD), obsessive–compulsive disorder (IU-OCD), health anxiety (IU-HA), posttraumatic stress disorder (IU-PTSD), panic disorder (IU-PD), specific phobia (IU-Phobia), and major depressive disorder (IU-MDD). Participants rated items on a five-point scale ranging from not at all (0) to extremely (4). The evidence demonstrated excellent psychometric properties (30). The disorder-specific IU-GAD, IU-SAD, IU-OCD, and IU-PD subscales were utilized in the current study. In the current work, the internal consistency of the subscales were as follow: IU-GAD (.82), IU-SAD (.87), IU-OCD (.84), and IU-PD (.92).
Metacognition Questionnaire (MCQ-30) (31): The MCQ-30 was used to measure metacognitive beliefs of participants about their worry and thoughts. This scale consists of five subscales; positive beliefs about worry, negative metacognitions about the uncontrollability and danger of worry, cognitive confidence, need to control thoughts, and cognitive self-consciousness (31). Responses were rated on a four-point Likert scale from do not agree (1) to agree very much (4). The alpha coefficients for Iranian sample for total scale was .91 and for the subscales were ranged from .71 to .87 (32). In the current study, we used negative metacognitions about the uncontrollability and danger of worry subscales. Internal consistency of the subscale was .87.
Brief Fear of Negative Evaluation Scale, Straightforward Items (BFNE-S) (33): BFNE-S adopted from BFNE (Leary, 1983) and comprises 8 straightforwardly- worded items with a 5-point Likert-type scale (0 = not at all characteristic of me; 5 = extremely characteristic of me). This scale measures the irrational thoughts related to being judged in a hostile way (34). The evidence established good psychometric properties in Iranian population (35).
Obsessive-Beliefs Questionnaire-44 (OBQ-44) (36): The self-report OBQ-44 was developed from OBQ-87 by obsessive compulsive cognitions working group(36). It assesses dysfunctional beliefs about development and maintenance of obsessive-compulsive disorder (37). The OBQ-44 consists of three subscales: Responsibility/Threat Estimation (OBQ-RT), Perfectionism/Certainty, Importance/Control of Thoughts. Participants showed their level of agreement on a 7-point Likert-type scale from disagree very much (-3) to neutral (0) to agree very much (+ 3). This scale has good internal consistency and criterion validity in clinical and non-clinical samples (38). In Iranian population, it showed good test-retest and internal consistency reliability and discriminant validity (39). In the current study we used OBQ-RT subscale Internal consistency of the subscale was .88.
Agoraphobic Cognitions Questionnaire (ACQ) (40): This 14-item scale assesses thoughts concerning negative consequences of experiencing anxiety and was designed to assess aspects of fear (panic attacks) in agoraphobics. The ACQ comprises two 7-item subscales: physical concerns and social/behavioral concerns. Responses were rated on a 5-point Likert scale from thought never occurs (1) to thought always occurs (5). Researches have shown good discriminant and construct validity and reliability of the scale (40). Psychometric research showed good sensitivity and validity in Iranian population (41). In the current study, internal conssitency of the scale was .86.
Generalized Anxiety Disorder-7 (GAD-7) (42): The 7-item GAD-7 was designed to identify probable cases of generalized anxiety disorder. Individuals were asked “how often, during the last 2 weeks, they were bothered by such symptoms.” Responses were rated on a 4-point Likert scale from not at all (0) to nearly every day (4). Psychometric research in Iranian population showed good reliability and validity (43). In the current study, internal conssitency of the scale was .87.
Social Interaction Phobia Scale (SIPS) (44): SIPS comprise 14 items assessing social phobia symptoms. Each item is measured on a 5-point Likert scale ranging from 0 (not at all characteristic or true of me) to 4 (extremely characteristic or true of me) and participants showed how often they were bothered by each symptom, during the past week. This scale comprises of 3 subscales: social interaction anxiety, fear of overt evaluation, and fear of attracting attention. The SIPS had high internal consistency (.92), test-retest reliability, and convergent validity (44). Psychometric research in Iranian students indicated good reliability and validity (45). In the current study, internal conssitency of the scale was .93.
Obsessive Compulsive Inventory – revised (OCI-R) (46): The OCI-R measures symptoms of obsessive-compulsive disorder (OCD). It contains 18 items and has six subscales: washing, checking, obsessions, mental neutralizing, ordering, and hoarding, rated on a 5-point Likert-type scale ranging from not at all (0) to extremely (4). Respondents described how much they felt distressed or bothered by each symptom, during the past month. Psychometrics evidence showed excellent properties (46). Internal consistency in Iranian students was satisfactory (47). In the current study, internal conssitency of the scale was .90.
The Panic Disorder Screener (PADIS) (48): PADIS is a 4-item scale identifying panic disorder in the community and assessing severity of symptoms. The PADIS had good reliability and validity, sensitivity (.77), specificity (.84), and internal consistency (48). In the current study, internal conssitency of the scale was .88.
2.4. Data analysis
We used SPSS 25.0 to calculate descriptive statistics and correlation matrix between measured variables. Correlation matrix were examined by calculating Pearson correlation coefficient. The correlation matrix between the observed variables showed no multiple linearity between them (49).
The measurement models were evaluated by confirmatory factor analysis (CFA) and hypothesized model was assessed by SEM with maximum likelihood estimation conducted in Mplus 7.4. For evaluation of measurement and structural model, fit indices, factor loadings, and modification indices were considered. Model fit indices included the x2/df ratio, Tucker-Lewis index (TLI), comparative fit index (CFI), root mean square error of approximation (RMSEA), and standard root mean square residual (SRMR). For evaluating the strength of structural pathways, standardized estimates were utilized. Bootstrapping with at least 1000 repeated samples was used for estimating the strength of the total and specific indirect effects.