[Changes in slow evoked potentials in depressed patients treated with amitriptyline and oxaprotiline]

Using a simple S1S2-R paradigm, acoustically evoked potentials, CNV, and PINV were recorded in 59 patients with major depressive disorder before and during a 4 week double blind pharmacological treatment with either amitriptyline (AT) or oxaprotiline (OT). In parallel, 30 healthy subjects were investigated 3 times, in identical intervals of 2 weeks. In the depressed state patients exhibited significantly smaller CNVs than the controls. In the AT-group clinical improvement and drug plasma levels of nortriptyline (NT, the principal metabolite of AT and an active antidepressant by itself) were positively related to increases in CNV-area; in the OT-group the reverse was true: increase in CNV-area was related to smaller OT plasma levels and less favourable outcome. The control group displayed a steady decline in CNV area during the 3 test sessions. N1P2 amplitude and PINV were not significantly different between groups and exhibited only minor variations during treatment.