Background. The aim of study was to investigate the antidepressant action of single ketamine infusion, in patients with bipolar depression receiving mood-stabilizing drugs which have not improved after treatment with antidepressants.
Methods. The study comprised 25 patients (21 women, 4 men), aged 27 to 67 years with depressive episode in the course of bipolar mood disorder (BD). All patients received at least one mood-stabilizing medication of ﬁ rst or/and second generation and their depression was resistant to antidepressant treatment. After discontinuation of antidepressant drugs for at least 7 days, patients received intravenous infusion of ketamine (0,5 mg/kg body weight). Psychometric assessment was done using 17-item Hamilton Depression Rating Scale (HDRS) before the infusion, after 6, 12, 24 hours and on 3, 7, 10 and 14 day after ketamine.
Results. The mean intensity of depression before ketamine infusion on HDRS was 21±5 points, reduced to 19±8 after 6 h, to 16±9 on the second day, to 12±7 on the 7 th day, and to 11±7 points on the 14 th day after ketamine. Response to treatment (reduction of ≥50% on HDRS) in one patient occurred after 6 hours, in ¼ of patients after 24 hours and in 52% of patients after 7 and 14 days. Four patients obtained remission (≤7 points on HDRS) on the second day after infusion, eight were in remission after 7 days, and twelve after 14 days. The infusion was well tolerated.
Conclusion. The results conﬁ rm a rapid antidepressant effect of ketamine infusion, sustained for at least 14 days, in a signiﬁ cant proportion of patients with depression in the course of BD, receiving mood-stabilizing drugs and resistant to previous treatment with antidepressants.