Validation of the general health questionnaire-12 using a sample of employees from England's health care services

Psychiatric interviews were carried out to validate the General Health Questionnaire-12 (GHQ-12; Goldberg, 1972) for use with staff of England's National Health Service (NHS), and to determine the appropriate threshold score to identify probable cases. In a sample of 551 NHS staff, the correlation between the GHQ-12 and the Clinical Interview Schedule-Revised (CIS-R) was found to be .70. The receiver operating characteristic showed that a 3/4 threshold, higher than used in all but one previous study, gave the best conservative estimate of minor psychiatric morbidity. This threshold gave an estimated sensitivity of the GHQ-12 of .69 and specificity of .88. It reduced case rates by between 8% and 17% as compared with lower possible thresholds. Convergent and discriminant validation of the GHQ-12 was demonstrated through comparison with other measures of mental and physical health.