Botulinum toxin therapy of bipolar depression: A case series.

We and others have recently found that botulinum toxin injected into the brow muscles has significant antidepressant properties as compared to placebo in randomized controlled trials in patients with major depressive disorder. However, data for the treatment of bipolar depression with botulinum toxin is lacking. We report here six patients with bipolar disorder experiencing moderate to severe depressive episodes who were treated on a compassionate basis with botulinum toxin given their persistent depressive symptoms and adverse side effects from medications. Four of six patients with bipolar depression experienced a remission following treatment with botulinum toxin, and the other two patients experienced a reduction of depressive symptoms. When the effect of botulinum toxin on the frown muscles began to wear off, depressive symptoms returned and retreatment with botulinum toxin provided successful relief of depressive symptoms again.