Short-term antidepressant treatment of bipolar depression: are ISBD recommendations useful in clinical practice?

The study aimed to test the effectiveness of the ISBD Guidelines for short-term AD treatment of BP depression.

The study sample included 255 patients with mood disorders (154 UP, 49 BP-I, 52 BP-II). Response was defined as a HDRS21 total score<7 at 12 weeks of treatment and remission as a ≥50% reduction of baseline HDRS21 total score sustained for 8 weeks.

Response was achieved by 64.9% of patients with UP disorder, 75.5% of patients with BP-I disorder and 75.0% with BP-II disorder without significant differences (χ²=3.0, p=0.219). The remission rate did not differ significantly among groups (χ²=3.8, p=0.151). The dropout rate was significantly higher for patients with UP (18.2%) than for patients with BP-I (2%) and BP-II (7.7%) disorder (χ²=10.1, p=0.006). Concerning AD safety, one patient with BP-I depression committed a suicide attempt and AD-emerging switch was observed in 2.9% of patients, 2 with BP-I and 1 with BP-II disorder.

The observational nature of the study and unblinded outcomes assessment.

Our findings confirm the usefulness of ISBD Guidelines for short-term AD treatment of BP depression. These patients appear to have similar response and remission rate to those observed in UP depression and do not exhibit significant switch rates or risk of suicide. Our results are limited to patients with pure bipolar depression (excluding those with broadly defined mixed states), treated with ADs-mood stabilizers combination. We suggest to partially modify ISBD Recommendations 1 and 4, to include potential responders and to improve safety.