Altered electrophysiological parameters of recognition memory in remitted patients with an affective disorder after amantadine treatment

There is general agreement that depression influences memory functions. Few studies have investigated whether such cognitive deficits also exist in the remitted phase of the disease. Amantadine has been suggested to demonstrate antidepressive properties. We investigated remitted patients after a depressive episode with regard to possible changes of event-related potentials (ERPs) in a picture recognition paradigm after treatment with amantadine. Twelve remitted patients (ICD-10: F31, F32 or F33) were recruited and treated randomly either with amantadine (200mg/day) or placebo in a double-blind cross-over design. ERPs were performed before and after a treatment period of 6-weeks (wash-out period=7 days). Comparison between week 0 and week 14 were carried out with ERPs and LORETA using a statistical analysis based on voxel-by-voxel t-tests. The clinical assessment showed no significant changes (HAMD scores, p=0.303). LORETA-analysis before (week 0) and after treatment (week 14) with amantadine revealed significant differences with a decreased brain activity in the left Inferior Temporal Gyrus (BA=37) (time window 300–450ms), which was followed by a decreased activity in the left Inferior Parietal Lobule (BA=40) (time window 450–600ms) at week 14 (all p<0,05). Amantadine seems to influence cognitive parameters in remitted patients. Further studies regarding the therapeutic role of amantadine in patients with affective disorders are considered.