Low frequency daily left prefrontal rTMS improves mood in bipolar depression: A placebo-controlled case report

Preliminary studies in unipolar depression indicate that daily left prefrontal repetitive transcranial magnetic stimulation (rTMS) reduces symptoms of depression. rTMS treatment of depression occurring in the setting of bipolar disorder has been less well studied. To assess the efficacy and toxicity of rTMS in the depressed phase of bipolar disorder, we treated a man with bipolar disorder who was known to develop hypomania and mania with conventional antidepressants. A 47 year old man with Bipolar Disorder type 1, depressed phase, was entered into a double-blind parallel treatment trial of left prefrontal rTMS. He was randomized to receive left prefrontal rTMS at low frequency (5 Hz) for 2 weeks, which was then followed by an open phase. The patient's Hamilton Depression scores decreased 44 per cent across the first 2 weeks. In an open extension, his mood further improved over another 2 weeks and he was gradually tapered from rTMS treatments. He had no side effects. Importantly, he did not develop mania, as had occurred with all prior antidepressant trials. After several months he experienced a recurrence of depressive symptoms, was retreated, and re-responded. Further studies are warranted to investigate the optimum dose, duration, location and frequency of rTMS treatments for the depressed phase of bipolar disorder.