The symptom check-list, SCL-90-R: its use and characteristics in chronic pain patients.

The SCL-90-R is a widely-used questionnaire for self-report of psychological distress and multiple aspects of psychopathology, as part of the evaluation of chronic pain patients and other non-psychiatric populations. The aim of this study is the presentation of clinical results of this multidimensional questionnaire in a convenience sample of 3540 chronic pain patients treated in a multidisciplinary pain centre. Confirmatory Factor Analysis (CFA), Exploratory Factor Analysis (EFA), single scale factor analyses and Cronbach's alphas are used to assess the internal structure and correlation to other instruments (CES-D, STAI, MPSS) to assess construct validity. It is shown that the 9 dimensions postulated by Derogatis et al. (1977 a) cannot at all be distinguished in chronic pain patients. The use of single subscores of the SCL-90-R, often employed as a screening instrument for specific diagnoses, such as depression, is at least questionable in chronic pain patients.