Mood disturbance versus other symptoms of depression in multiple sclerosis.

We administered the Multiscale Depression Inventory (MDI) and the Beck Depression Inventory (BDI) to 84 multiple sclerosis (MS) patients, 101 patients diagnosed with major depression and 87 nonmedical, nonpsychiatric controls. The MDI consists of three separate depression scales measuring mood, vegetative, and evaluative symptoms. We found that: (a) MS patients did not significantly differ from the controls in mood symptoms, (b) the depression prevalence rate in MS patients was significantly lower when measured by the mood scale (17.7%) than by the BDI (30.5%) or MDI total score (26.6%), and (c) MS patients showed significantly less mood disturbance than a non-MS comparison group matched on BDI measured depression severity. We suggest that the inclusion of nonmood symptoms in self-report depression scales may artificially raise both prevalence rates and severity ratings of MS related depression and that the most valid measure of depression in MS is mood disturbance.