An expanded childhood anxiety sensitivity index: its factor structure, reliability, and validity in a non-clinical adolescent sample
Introduction
Anxiety sensitivity refers to the fear of anxiety-related bodily sensations that are interpreted as having potentially harmful somatic, psychological, or social consequences (e.g., Taylor, 1995). Research in adult populations has indicated that anxiety sensitivity plays a role in the aetiology and maintenance of anxiety disorders, in particular panic disorder (e.g., Rachman, 1998). There is evidence to show that anxiety sensitivity is also involved in fear and anxiety of children and adolescents. A number of studies have found that anxiety sensitivity in children and adolescents correlates in a theoretically meaningful way with other anxiety measures (Chorpita, Albano, & Barlow, 1996; Muris, Schmidt, Merckelbach, & Schouten, 2001; Silverman, Fleisig, Rabian, & Peterson, 1991; Weems, Hammond-Laurence, Silverman, & Ginsburg, 1998). Furthermore, Rabian, Peterson, Richters, and Jensen (1993) compared levels of anxiety sensitivity in children with anxiety disorders, children with disruptive disorders, and children with no diagnosis. Results showed that children with anxiety disorders displayed significantly higher anxiety sensitivity scores than children with no diagnosis, whereas children with disruptive disorders scored in between. Finally, Lau, Calamari, and Waraczynski (1996) examined the relationship between anxiety sensitivity and panic disorder symptoms in normal adolescents. These authors found significant associations between anxiety sensitivity and the number of experienced panic attacks, the level of distress caused by the panic attacks, and the judged seriousness of the attacks (for similar findings, see Kearney, Albano, Eisen, Allan, & Barlow, 1997; Mattis & Ollendick, 1997).
In children and adolescents, anxiety sensitivity is measured by means of the Childhood Anxiety Sensitivity Index (CASI; Silverman et al., 1991), which is an age-downward modification of the Anxiety Sensitivity Index (ASI; Reiss, Peterson, Gursky, & McNally, 1986), the most widely used instrument for assessing anxiety sensitivity in adults. The CASI consists of 18 items such as “It scares me when I feel shaky”, “It scares me when my heart beats fast”, and “It scares me when I feel nervous”; children and adolescents are asked to rate the extent to which each item applies to them (none, some, or a lot). Previous studies have consistently shown that the CASI is a reliable and valid questionnaire for measuring anxiety sensitivity in both clinical and non-clinical samples of children and adolescents (e.g., Rabian, Embry, & MacIntyre, 1999; Silverman et al., 1991).
There has been considerable debate on the factor analytic structure of anxiety sensitivity. Although there is consensus that anxiety sensitivity should be regarded as a hierarchically organised construct consisting of several lower-order factors which load on a single higher-order factor (see, e.g., Cox, Parker, & Swinson, 1996; Taylor & Cox, 1998a; Zinbarg, Barlow, & Brown, 1997), the exact number and nature of the lower-order factors remain to be disclosed. Identification of distinct anxiety sensitivity factors seems important because these factors may reflect specific mechanisms that make individuals prone to develop specific types of fear and anxiety (see Cox, 1996). For example, the factor ‘fear of cardiovascular symptoms’ may lead to a panic attack with catastrophic thoughts about dying, whereas the factor ‘fear of publicly observable symptoms’ may give rise to social anxiety with thoughts about personal weakness.
Previous factor analytic studies seem to indicate that anxiety sensitivity in children and adolescents can be best conceptualised as a hierarchical model with either three or four lower-order factors loading on one higher-order factor (i.e., ‘anxiety sensitivity’). For example, on the basis of their study in normal and clinically children aged 7 to 16 years, Silverman, Ginsburg, and Goedhart (1999) concluded that a hierarchical structure with three lower-order factors, i.e., ‘fear of physical symptoms’, ‘fear of mental incapacitation’, and ‘fear of social evaluation’, probably is the most plausible representation of the anxiety sensitivity construct. Highly similar factors were obtained by Muris et al. (2001) in their sample of normal adolescents aged 13 to 16 years. Meanwhile, it is important to note that in both studies some indications were found for a four-factor solution providing an even better fit for the data. The problem, however, is that the CASI, just like its adult version (the ASI), simply contains too few items (i.e., 18 and 16, respectively) to examine this issue and to reliably detect the major factors of anxiety sensitivity.
In an attempt to deal with this problem, Taylor and Cox (1998b) recently developed an expanded scale of anxiety sensitivity for adults, the Anxiety Sensitivity Index — Revised (ASI-R), which consists of 36 items each referring to one of the major domains of anxiety sensitivity suggested by earlier studies. The factor structure of the ASI-R was examined in a sample of adult psychiatric outpatients (N=155). Results indicated a hierarchical structure with four lower-order factors loading on one higher-order factor. The lower-order factors were (1) ‘fear of cardiovascular symptoms’, (2) ‘fear of publicly observable anxiety reactions’, (3) ‘fear of cognitive dyscontrol’, and (4) ‘fear of respiratory symptoms’.
Silverman et al. (1999) have noted that it would be of interest to examine whether this hierarchical four-factor structure of anxiety sensitivity can also be obtained in children and adolescents when using an expanded childhood measure of anxiety sensitivity. The main purpose of the present study was to investigate just this issue. Following Taylor and Cox (1998b), a revised version of the CASI, i.e., the CASI-R, was constructed. The factor structure of the CASI-R was examined by carrying out confirmatory factor analysis. This statistical technique makes it possible to examine to what extent the data are in line with a hypothesised factor structure. Two models had our special attention. First of all, the hierarchical model with four lower-order factors (see supra) loading on one higher-order factor as reported by Taylor and Cox (1998b) for the (adult) ASI-R was tested. Second, a more parsimonious three-factor model (in which ‘fear of cardiovascular symptoms’ and ‘fear of respiratory symptoms’ were combined to one factor labelled ‘fear of physical symptoms’), as suggested in previous research on childhood measures of anxiety sensitivity (Silverman et al., 1999; Muris et al., 2001), was investigated.
An additional aim of the current study was to investigate the psychometric properties of the CASI-R. First, the reliability (internal consistency) of the various CASI-R factors/scales was investigated. Second, the convergent and discriminant validity of the CASI-R was addressed. More specifically, relationships between the CASI-R and the original childhood index of anxiety sensitivity (i.e., the 18-item CASI), the trait anxiety version of the State–Trait Anxiety Inventory for Children (STAIC; Spielberger, 1973), and measures of anxiety disorders symptoms and depression were examined. It was hypothesised that CASI-R scores would correlate strongly with the original CASI (i.e., r>0.90), moderately with trait anxiety (r in the 0.60 or 0.70 range; see Taylor & Cox, 1998b; Muris et al., 2001), and with all of the anxiety disorders but most strongly with symptoms of panic disorder and agoraphobia. Furthermore, in keeping with Muris et al. (2001), it was expected that anxiety sensitivity and trait anxiety both have independent power in predicting symptoms of anxiety disorders and depression, suggesting that both constructs should be viewed as distinct vulnerability factors to psychopathology.
Section snippets
Participants and procedure
Five-hundred-and-eighteen adolescents (239 boys and 279 girls; mean age=14.9 years, SD=1.9, range 12–18 years; percentages of adolescents per age level were 12.7% 12-year-olds, 17.6% 13-year-olds, 13.3% 14-year-olds, 17.2% 15-year-olds, 12.2% 16-year-olds, 15.4% 17-year-olds, and 11.6% 18-year-olds) were recruited from a regular secondary school. Participants completed a set of questionnaires (see below) in their classrooms. The teacher and a research assistant were always available to provide
Factor structure of the CASI-R
Confirmatory factor analysis indicated that the hierarchical factor structure with four lower-order factors (i.e., ‘fear of cardiovascular symptoms’, ‘fear of publicly observable anxiety reactions’, ‘fear of cognitive dyscontrol’, and ‘fear of respiratory symptoms’) loading on a single higher-order factor (i.e., ‘anxiety sensitivity’) provided a good fit for the CASI-R data. Goodness-of-fit indices for this model were: chi square/degrees of freedom=3.6, RMR=0.05, RMSEA=0.07, CFI=0.95,
Discussion
The current data show that anxiety sensitivity in children and adolescents as measured by the CASI-R can best be conceptualised as a hierarchical construct with four lower-order factors loading on a single higher-order factor. The lower-order factors were ‘fear of cardiovascular symptoms’, ‘fear of publicly observable anxiety reactions’, ‘fear of cognitive dyscontrol’, and ‘fear of respiratory symptoms’. Note that these findings were highly similar to those reported by Taylor and Cox (1998b)
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2014, Journal of Affective DisordersCitation Excerpt :Anxiety sensitivity (AS) is defined as the belief that the experience of bodily symptoms related to anxiety has negative implications in terms of causing illness, loss of control (e.g., feeling sick might entail medical consequences), embarrassment (e.g., feeling shaky is regarded as visible to others), or additional anxiety (e.g., a fast heart rate is the cause for concern; Reiss and McNally, 1985). There is evidence that AS is more marked among clinically anxious and highly anxious community children (9–14 years) in comparison to non-anxious children (Muris et al., 2001; Muris, 2002; Rabian et al., 1993; Vasey et al., 1995). Whereas anxiety sensitivity is most strongly associated with panic disorder in adulthood (Olatunji and Wolitzky-Taylor, 2009), panic disorder is rare in childhood (Ollendick et al., 1994) and, in fact, Essau et al. (2010) showed, in a large community sample (N=1292) of adolescents (12–17 years), that AS was most strongly associated with symptoms of social anxiety (r=.50) in comparison to all other anxiety disorder symptoms, including panic symptoms (r=.40).
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2012, Journal of Anxiety DisordersCitation Excerpt :These are thus included purely for descriptive purposes. Absolute fit indices included; chi-square divided by the degrees of freedom (the lower the value the better the fit; Muris, 2002), Root Mean Square Error of Approximation (RMSEA; should approximate .08 for approximate fit and .05 for close fit; Browne & Cudeck, 1993) and Akaike's Information Criterion (AIC; smaller values indicate better fit). Additionally, the Tucker–Lewis Index (TLI; Tucker & Lewis, 1973; smaller values indicate better fit) was included to compare the fit between models.
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2009, Journal of Anxiety DisordersCitation Excerpt :Less broad physical factors, such as fear of respiratory symptoms (Deacon & Abramowitz, 2006; Muris, 2002; Taylor & Cox, 1998) or fear of cardiovascular symptoms (Muris, 2002; Taylor & Cox, 1998), have also been found. Additionally, previous studies have extracted a number of other cognitive factors, for example an emotional factor (Khawaja & Oei, 1992, 1998; Wenzel et al., 2006), a mental or cognitive functioning factor (Deacon & Abramowitz, 2006; Hicks et al., 2005; Khawaja & Oei, 1992, 1998; Muris, 2002), a social factor (Deacon & Abramowitz, 2006; Hicks et al., 2005; Khawaja and Oei, 1992; Lovibond & Rapee, 1993; Muris, 2002; Wenzel et al., 2006), or combinations of these, such as social-cognitive concerns (Zvolensky et al., 2003), fear of psychosocial consequences (Marks et al., 1991), or fear of psychological symptoms (Cox et al., 1995). As results of prior studies do not provide a clear hypothesis about the structure of cognitive symptoms, further studies with an explorative approach to data collection and analysis are needed.
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