Detecting psychiatric disorders in medical practice using the General Health Questionnaire. Why do cut-off scores vary?

• Published in: Psychological medicine Vol. 25; no. 1; p. 165
• Main Authors: van Hemert, A M, den Heijer, M, Vorstenbosch, M, Bolk, J H
• Format: Journal Article
• Language: English
• Published: England 01.01.1995
• Subjects: Adolescent; Adult; Female; Humans; Male; Mental Disorders - diagnosis; Mental Disorders - psychology; Middle Aged; Netherlands - epidemiology; Patient Care Team - statistics & numerical data; Personality Inventory - statistics & numerical data; Psychometrics; Psychophysiologic Disorders - diagnosis; Psychophysiologic Disorders - psychology; Referral and Consultation - statistics & numerical data; Reproducibility of Results; Somatoform Disorders - diagnosis; Somatoform Disorders - psychology
• ISSN: 0033-2917
• DOI: 10.1017/S003329170002818X

In this study we assessed the accuracy of the General Health Questionnaire in detecting psychiatric disorders in general medical out-patients. A total of 290 newly referred patients were interviewed with the Present State Examination. Prior to the interview, 112 patients completed the full GHQ-60, 100 completed the GHQ-30 and 78 completed the GHQ-12. Data from the first group were used to study the full GHQ-60, together with the GHQ-30 and and GHQ-12, when disembedded from the full questionnaire. In a comparison between the disembedded and the separate versions of the GHQ-30 and GHQ-12 we observed considerable variation in the cut-off scores where a certain sensitivity and specificity was attained. In ROC-analysis, the versions were not materially different in their discriminatory capacity (area under the curve). The use of different criteria to define a 'case' demonstrated that case severity was another source of increasing cut-off scores. Our data demonstrate that the use of disembedded or separate versions of the questionnaire, together with variation in the case criteria can be a major explanation for variation in cut-off scores that was observed in previous studies.