There is a need for a valid self-rating questionnaire to screen for psychiatric morbidity in patients with chronic fatigue syndrome (CFS). This study had the aim of assessing the utility and validity of two commonly used measures.
Scores obtained on the General Health Questionnaire (GHQ) and the Beck Depression Inventory (BDI) were compared with various diagnostic and severity ratings obtained via a validating clinical interview, the Schedules for the Clinical Assessment of Neuropsychiatry (SCAN) in 95 consecutively referred subjects at a medical out-patient clinic who fulfilled standard criteria for CFS, and 48 healthy controls. Outcome measures were validating coefficients and receiver operating characteristics (ROC) for different thresholds and scoring on GHQ and BDI and index of definition (ID) as measured by SCAN; and Pearson and point by serial correlation coefficients for different diagnostic groups derived via SCAN and defined according to ICD–10 and DSM–III–R.
GHQ and BDI perform poorly as screeners of psychiatric morbidity in CFS subjects when compared with various SCAN derived ratings although results for controls are comparable with other studies.
Neither the GHQ nor BDI alone can be recommended as screeners for psychiatric morbidity in CFS subjects.