Exploration of the factor structure of the physical symptoms questionnaire (PSQ-51). Comparisons between Dutch and English samples

The Physical Symptoms Questionnaire (PSQ-51) is a Dutch-language self-report tool listing 51 physical symptoms that may occur in patients with known medical conditions, somatic symptom disorders and the general population. However, the tool is currently only available in Dutch and is yet to be translated or validated into English for utility with English-speaking populations. This study aimed to translate and validate an English version of the tool and determine the PSQ-51's factor structure in both Dutch and UK samples. An English version was translated and then validated through back-translation and refined for clarity. Data from three Dutch samples (general population [n = 1699], general practice[n = 775], and psychiatric outpatients[n = 1404]) and one UK general population sample (n = 294) were then analysed to explore the factor structure. An iterative exploratory factor analysis (EFA) on the Dutch psychiatric sample revealed a seven-factor solution including symptom clusters: General Malaise, Autonomic, Musculoskeletal, Gastrointestinal, Loss of Function, Hot Flushes, and Urogenital symptoms. Confirmatory factor analysis (CFA) tested this model across the Dutch and UK samples, with mixed results for fit indices, although good internal reliability was demonstrated. Findings indicate partial cross-cultural consistency in the factor structure. Substantial differences in symptom prevalence between Dutch and UK population samples were observed, possibly due to cultural and situational factors. The PSQ-51 shows promise for assessing somatic symptom burden, for example in multimorbidity or in complex somatic symptom disorders, where it may enhance clinical consultations by identifying symptoms to address clinical complexity. Further research is needed to explore its applicability in diverse populations and refine its factor structure for broader clinical utility.