Prediction of caseness for mental pathology in Swiss conscripts: the Self-Screen Prodrome.

Background: Basic military training (BMT) is an environment of higher stress levels than are encountered in civilian life. It may trigger mental disorders in predisposed individuals. To reduce BMT attrition because of mental problems a psychiatric assessment is part of the Swiss recruitment process. An initial screening survey that identifies vulnerable individuals will be useful to save both cost and effort when dealing with large populations, such as military draftees. Aims of this investigation are to verify the psychometric properties of the Self-Screen Prodrome (SPro), a newly developed, short screening tool for psychopathology, and to validate it against the Symptom Checklist-90-Revised (SCL-90-R), a well-established self-assessment instrument.

Method: A sample of 12,380 male conscripts from the year 2003 were administered both the SPro and the SCL-90-R. Vulnerability was operationalized using the "caseness" definition of the SCL-90-R.

Results: Factor analysis demonstrated unidimensional scaling of the SPro, and this was supported by high internal reliability. Scores of nine or more symptoms on the SPro scale were found to successfully discriminate between SCL-90-R positive and negative cases. It is thus an adequate measure of general psychopathology (caseness). The association of p = 0.77 between the SPro and the SCL-90-R Global Severity Index (GSI) clearly supports concurrent validity. Our data also demonstrated that the SPro can distinguish individuals with self-reported mental health problems from those with no or few reported symptoms (cutoff > or = 9; sensitivity 89.3%; specificity 84.9%; AUC 0.942; CI 95% 0.935-0.948).

Conclusion: Though replication and further research are needed, the SPro scale may currently be a useful screening tool for initial screening in a two-stage process of early detection of psychopathology.