The Penn State Worry Questionnaire (PSWQ) is a widely used assessment of excessive worry. American undergraduate samples have predominately been used to evaluate its factor structure, which may not generalize to other developmental, cultural, and psychopathology populations. The present study tested the PSWQ's factor structure across three diverse samples: American undergraduate students (n = 3,243), Dutch high school students (n = 3,906), and American adults with psychopathology (n = 384). Exploratory, confirmatory, and multigroup confirmatory factor analyses were conducted. Measurement invariance and concurrent validity were also tested. Method-factor and two-factor models were largely equivalent and superior to a one-factor model. Invariance tests supported configural and metric invariance but only partial scalar invariance. Positively worded items but not negatively worded items demonstrated concurrent validity with anxiety and depression symptom measures and diagnoses. Overall, the PSWQ appears to measure a unitary construct. Present results warrant further testing of the PSWQ across diverse samples.
Keywords: Penn State Worry Questionnaire; anxiety; depression; factor structure; measurement invariance.