Multiple Treatment Study Using Low Field Magnetic Stimulation for Bipolar Depression

Low Field Magnetic Stimulation is an electromagnetic intervention being investigated at McLean Hospital because of its effect on symptoms of depression. It consists of pulsed electric fields that are induced remotely in the head by a portable coil. It has been observed to have mood elevating effects in depressed patients with Bipolar Disorder (BPD). These effects are immediate, occurring upon completion of a 20 minute treatment. LFMS is unique because of its low electric field strength, and because of its high frequency operation, compared to other electromagnetic treatments. While other treatments such as Electroconvulsive Therapy (ECT) use electric fields equivalent to \> 100-200 Volts/meter to affect the brain, LFMS uses \<1 V/m. Such a low electric field strength indicates that another mechanism is activated by LFMS, and this provides a possibility for a new treatment. It may also give insight into causes of depression. LFMS is also unique because it has an immediate effect. This immediate effect may have implications for emergency treatment. The purpose of this study is to observe the response to LFMS in depressed BPD subjects with the aim of assessing the effects of multiple treatments, and of observing the duration of the mood improvement.To do so, the investigators propose to study 72 subjects in a protocol of three treatments in three days. Subjects will be rated before and after each treatment, and will return for mood ratings at one week after treatment. Investigators hope that this characterization of LFMS will allow clinical research groups to perform large trials and to evaluate its clinical effectiveness in patient populations.