Background. In recent years the 12-item General Health Questionnaire (GHQ-12) has been
extensively used as a short screening instrument, producing results that are comparable to longer
versions of the GHQ.
Methods. The validity of the GHQ-12 was compared with the GHQ-28 in a World Health
Organization study of psychological disorders in general health care. Results are presented for
5438 patients interviewed in 15 centres using the primary care version of the Composite
International Diagnostic Instrument, or CIDI-PC.
Results. Results were uniformly good, with the average area under the ROC curve 88, range
from 83 to 95. Minor variations in the criteria used for defining a case made little difference to
the validity of the GHQ, and complex scoring methods offered no advantages over simpler
ones. The GHQ was translated into 10 other languages for the purposes of this study, and
validity coefficients were almost as high as in the original language. There was no tendency for
the GHQ to work less efficiently in developing countries. Finally gender, age and educational
level are shown to have no significant effect on the validity of the GHQ.
Conclusions. If investigators wish to use a screening instrument as a case detector, the shorter
GHQ is remarkably robust and works as well as the longer instrument. The latter should only
be preferred if there is an interest in the scaled scores provided in addition to the total score.