Purpose: While the General Health Questionnaire (GHQ) has an excellent screening performance among outpatients and in the community, its accuracy to detect mental disorders among non-psychiatric inpatients was reported to be lower. The aim of the present study was to compare the criterion validity of different scoring methods, i.e. the Bimodal scoring, Likert scoring, Modified Likert scoring and Chronic scoring, of the 30-, 20- and 12-item version of the GHQ.
Methods: The GHQ was available from 511 inpatients recruited from surgical, medical, gynaecological and physical rehabilitation wards. The Clinical Interview Schedule was performed for psychiatric case-identification and was used as external care criterion.
Results: Sensitivities of all versions were between 0.612 and 0.701, and specificities between 0.601 and 0.759. The Overall Misclassification Rate (OMR) varied for the Bimodal and the Modified Likert scoring method between 0.257 and 0.281, for the Likert and the Chronic scoring method between 0.325 and 0.386. Overall, the Bimodal and the Modified Likert scoring method showed significantly better specificity and OMR than the Likert and the Chronic scoring method, while we could not find any differences for sensitivity.
Conclusions: Overall, the Bimodal and the Modified Likert scoring method seem to be more accurate than the Likert and the Chronic scoring method. Nevertheless, due to the high misclassification, none of these versions can be recommended for routine screening among non-psychiatric inpatients.