Controversy exists over antidepressant use in bipolar II depression.
To compare the safety and effectiveness of antidepressant v. mood stabiliser monotherapy for bipolar type II major depressive episodes.
Randomised, double-blind, parallel-group, 12-week comparison of venlafaxine (n = 65) v. lithium (n = 64) monotherapy in adult out-patients (trial registration number NCT00602537).
Primary outcome – venlafaxine produced a greater response rate (67.7%) v. lithium (34.4%, P<0.001). Secondary outcomes – venlafaxine produced a greater remission rate (58.5% v. 28.1%, P<0.001); greater decline in depression symptom scores over time (β=–5.32, s.e. = 1.16, χ2 = 21.19, P<0.001); greater reduction in global severity scores over time (β=–1.05, s.e. = 0.22, χ2 = 22.33, P<0.001); and greater improvement in global change scores (β=–1.31, s.e. = 0.32, χ2 = 16.95, P<0.001) relative to lithium. No statistically significant or clinically meaningful differences in hypomanic symptoms were observed between treatments.
These findings suggest that short-term venlafaxine monotherapy may provide effective antidepressant treatment for bipolar II depression without a statistically significant increase in hypomanic symptoms relative to lithium.