Objective: Although depressive symptoms are preponderant in the course of bipolar (BP) disorders, the treatment of BP depression remains a controversial issue with different clinical approaches available. This review addresses the issues of whether antidepressants (ADs) are effective in treating acute and long-term BP depression, risks linked to ADs and what alternatives to ADs are available.

Methods: We searched the MEDLINE databases using the following syntax: [bipolar depression AND unipolar depression AND (antidepressants OR anticonvulsants OR lithium OR antipsychotics OR dopamine-agonists OR psychoeducation OR psychotherapy OR electroconvulsive therapy OR transcranial magnetic stimulation)]. The search included studies published up to 31 May 2009 and conducted on adults.

Results: In the acute treatment of BP depression ADs are effective with no differences among drug classes. However, neither the switch into (hypo)mania induction rate nor the suicide risk linked to AD use are definitely established. The effectiveness of long-term AD use is limited to highly selected samples of patients with positive acute response. The risk of long-term ADs causing cycle acceleration and rapid cycling induction concerns a subpopulation of patients. Valid alternatives to ADs in treating acute BP depression are quetiapine, an olanzapine–fluoxetine combination, and electroconvulsive therapy for more severe patients. Lamotrigine is effective and safe in preventing depressive relapses. Psychotherapy and psychoeducation represent effective adjunctive treatments.

Conclusion: In the treatment of BP depression there is not a specific effective treatment for all the patients. Interventions should therefore be personalised and the scientific evidence should be adapted to each patient's clinical features.