Diagnosing mental disorders in primary care: the General Health Questionnaire (GHQ) and the Symptom Check List (SCL-90-R) as screening instruments.

BACKGROUND: The treatment of mental disorders in Germany is mainly done by primary care physicians. Several studies have shown that primary care physicians have difficulty in diagnosing these disorders. Recently, several self-report questionnaires have been developed that can be used as screening instruments to identify psychopathology in primary care settings and in the community. The aim of this paper was to investigate the screening properties of the General Health Questionnaire (GHQ-12) and the Symptom Check-List (SCL-90-R) in a primary care setting in Germany.
METHOD: A randomly selected sample (n = 408) of adult outpatients from 18 primary care offices in Düsseldorf was screened using the German versions of the GHQ-12 and the SCL-90-R. A structured diagnostic interview (SCID) and an impairment rating (IS) were used as a gold standard to which both questionnaires were compared. Test performance was evaluated by receiver operating characteristic (ROC) analysis.
RESULTS: We found no difference in the performance of the general scores of the two questionnaires. Both instruments were able to detect cases. Complex scoring methods offered no advantages over simpler ones for the GHQ-12. ROC analysis confirmed that the SCL-90-R subscales "anxiety" and "depression" showed acceptable concurrent validity for the diagnostic groups anxiety and depression (according to DSM-III-R).
CONCLUSIONS: GHQ-12 and SCL-90-R appeared to be useful tools for identifying mental disorders in primary care practice and research. The use of GHQ-12 or SCL-90-R, employed as a first step, supplemented by a second-stage interview, may enhance the detection rate of mental disorder in primary care settings.