Developed in America in 1990, the Penn State Worry Questionnaire for Adults (PSWQ) is the measure most frequently used to assess trait pathological worry in adults (Meyer, Miller, Metzger, & Borcovec, 1990). The PSWQ is a 16-item self-report questionnaire, derived from a factor analysis of 161 items believed to be related to worry. It is intended to measure an individual’s disposition to worry, as well as the frequency, intensity, and tendency for worry to be generalised (Meyer et al., 1990). Respondents are asked to rate each item on a 5-point Likert scale ranging from 1 (“not at all typical of me”) to 5 (“very typical of me”). Eleven of the items are positively scored in the direction of pathological worry (e.g. “my worries overwhelm me”), while the remaining five items require reverse scoring and indicate worry is not a problem (e.g. “I never worry about anything”). The scores from each item are added together to yield a total score that ranges from 16-80, with higher scores representing higher levels of pathological worry (Meyer et al., 1990).
The PSWQ is not a diagnostic tool; however, it is useful as a screening tool to detect pathological worry, and to evaluate therapeutic changes on worry (Meyer et al., 1990). It also successfully distinguishes GAD from other anxiety disorder groups, such as Post Traumatic Stress Disorder (Brown, Antony, & Barlow, 1992). Most GAD patients tend to show higher PSWQ scores (above 50), although some people with other diagnoses may sometimes report PSWQ levels similar to those with GAD (e.g. depression in Starcevic, 1995). This may be the result of high levels of comorbid GAD, or possibly because the DSM-IV does not allow a diagnosis of GAD if symptoms occur during episodes of other disorders (Chelminski & Zimmerman, 2003).
The PSWQ has been shown to have good internal reliability in samples consisting of older adults with GAD (Generalised Anxiety Disorder), community samples, and undergraduates, with cronbach alphas ranging from .88 to .95 (Startup & Erickson, 2006). It has also demonstrated favourable test-retest reliability over 8-10 weeks in a sample of college students (r= 0.92) (Meyer et al., 1990). In both clinical and community samples, the PSWQ has shown high convergent validity with other worry questionnaire measures, such as The Worry Domains Questionnaire (r=.67) (Tallis, Eysenck, & Mathews, 1992), and the student worry scale (r=.59) (Davey, Hampton, Farrell, & Davidson, 1992), and has shown high discriminant validity as it correlates significantly with anxiety and depression as measured by the State Trait Anxiety Inventory (trait r= .64-.79, state r = .49) (Meyer et al., 1990; Spielberger, Gorsuch, Lushene, Vagg, & Jacobs, 1983) and the Beck Depression Inventory (r= .36-.62) (Beck, Ward, Mendelson, Mock, & Erbaugh, 1961; Meyer et al., 1990).
It is also important to consider whether scores remain stable across demographic groups, or if any individual factors impact the PSWQ’s psychometric properties. With the regard to gender, no differences have been found (Meyer et al., 1990). In addition, the PSWQ has demonstrated to be valid in cross cultural populations, yielding good psychometric properties in samples in Korea (Lim Kim, Lee & Kwon, 2008), India (Parikh & Chhibber, 2016), and Germany (Stöber, 1995). In contrast to ethnicity, age is a factor that may influence PSWQ scores. Older adults have reported significantly lower scores than younger adults in both community (Gillis et al., 1995) and clinical samples (Hopko et al., 2003). Furthermore, older age may also impact the psychometric properties, as the PSWQ has demonstrated reasonable internal reliability and validity for this age group, but poor test-retest reliability (Davey & Wells, 2006). When a test has poor test-retest reliability, it makes it unclear whether the data is an accurate representation of a participant’s performance or whether extraneous variables interfered.
A major limitation of the PSWQ is that it does not capture worry changes over short periods of time. In some situations, a more frequent assessment of pathological worry is needed. To meet the need for a more frequent worry assessment, Stober and Bittencourt (1998) developed the PSQW- Past Week for weekly assessments of worry which also has good psychometric properties. Overall, the PSWQ appears to have sound psychometric properties and sensitivity to treatment change. It is a good choice for research and clinical studies to assess the intensity of pathological worry and to discriminate GAD from other disorders (Turk, Heimberg, & Mennin, 2004).
References
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