A screening questionnaire for the detection of serious mental illness in the criminal justice system

The objective of the study was to develop a screening questionnaire for serious mental illness in magistrates' courts. Using the General Health Questionnaire (GHQ) and the Psychosis Screening Questionnaire (PSQ), with second phase interview with the Schedule for Clinical Assessment in Neuropsychiatry (SCAN), 2,920 attendees at two magistrates' courts were screened for serious mental illness. Weighted logistic regression analysis was used to identify the best subset of questions from the screening questionnaires (GHQ and PSQ) for inclusion into a short screening tool. Of the 2,920 court attendees screened, 1,306 were interviewed using the SCAN, of whom 113 had an ICD 10 diagnosis with an index of definition (ID) of 5 or more. Of these, 38 had a diagnosis of schizophrenia or other psychoses and 68 of depression or bipolar affective disorder. A short, 7-item screening questionnaire was developed, which detected 101 out of 113 cases (weighted sensitivity 89.4%) with 469 false positives (weighted specificity 60.7%). The questionnaire detected all 17 cases with severe depression and 33 out of 38 with schizophrenia. We concluded that this questionnaire may be a useful adjunct to the screening process for mental illness in magistrates' courts.