Objectives:
The efficacy of vortioxetine in major depressive disorder has been evaluated in many studies. However, there is a lack of studies assessing vortioxetine in bipolar depression.

Methods:
In 60 patients with bipolar depression, vortioxetine 10–20 mg daily was added to current mood stabilizing medication during 24-week, naturalistic, openlabel study. The most frequent mood stabilizers were lamotrigine, quetiapine, olanzapine, and valproates. The therapeutic efficacy was evaluated by the Clinical Global Impression – Improvement (CGI-I) and Clinical Global Impression – Severity (CGI-S) scales. Patients were classified as responding to vortioxetine when they achieved 1 or 2 points on the CGI-I scale at any stage of observation. The criterion of remission was defined as score 1 at the CGI-S.

Results:
73% of all patients (44/60) responded to vortioxetine and 52% (31/60) achieved clinical remission of depressive symptoms (in mean 8.97 ± 4.05 weeks). There were no significant associations between vortioxetine response/remission rates and: (1) the dose, (2) BD type, (3) clinical stage, (4) presence of rapid cycling, (5) history of psychotic symptoms, analyzed depressive symptoms, and (6) concomitantly used mood stabilizer. 4 patients (6.7%) stopped treatment due to adverse effects (nausea), and 7 patients (11.7%) discontinued treatment due to the phase switch. 14 patients (23%) experienced a loss of vortioxetine effectiveness after the initial response or remission.

Conclusions:
The results indicate relatively high rates of response and remission during 24-week treatment in depressed bipolar patients receiving vortioxetine concomitantly with a mood stabilizer. This may indicate that vortioxetine added to a mood stabilizer may constitute an efficient and well tolerated therapeutic option in bipolar depression.