Memory impairment in patients with late-onset major depression: the effect of antidepressant therapy

BACKGROUND: Cognitive deficits have been described in patients with major depression (MD), although many aspects remain unsettled. METHOD: During an episode of MD and after remission we used tasks exploring attention, implicit, anterograde and retrograde memory to investigate 48 drug-free patients aged over 50 years without dementia, comparing them with 15 normal volunteer controls (NC). We also evaluated the effect of antidepressant therapy (ADT) with fluoxetine (F) or reboxetine (R) at baseline (T0) and six months later (T6). RESULTS: 42 patients completed the study and 6 dropped out; 33 patients were considered "Remitters" (RP) (17 F pts and 16 R pts). At T0, the entire group of MD patients (MDP) had worse performances than NC in Mini Mental Status Examination (MMSE), Wechsler Memory Scale (WMS) total score (TS), in a few subtests of WMS and in autobiographical memory. RP at T0 had the same impaired tasks and at T6 had significantly improved in MMSE, WMS. TS and many memory tests but they still differed from NC in a few complex tasks requiring more cognitive effort. LIMITATIONS: The effects and differences between F and R must be viewed with caution considering the relatively small sample; only attention and memory were investigated. CONCLUSIONS: Our findings confirm a negative effect of depression on memory with a significant but incomplete improvement after remission and without differences between F and R. We speculate that both a "state" and a "trait" depressive component underlie this memory impairment.