ABSTRACT
Five brain stimulation techniques are being actively researched at the present moment as treatments for neuropsychiatric disorders. Only one of them, electroconvulsive therapy (ECT), is a clinically established treatment for different psychiatric disorders, including depression, mania, and catatonia. The four other methods, deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), and vagus nerve stimulation (VNS) are currently at different stages of research as potential clinical treatments of several psychiatric disorders, most importantly for treatment of refractory depression (TMS, MST, DBS, and VNS) and obsessive-compulsive disorder (DBS) and not in widespread clinical use. Even if their clinical utility is not yet established, they are valuable as research tools in the search of the underlying neurobiology of the investigated disorders and they may well mature into treatment options for patients that are resistant to conventional interventions. The important research activity in basic mechanisms of disease accompanying the clinical studies of these new brain stimulation techniques, in animal models as well as in humans will be of relevance to bipolar disorders, which are a heterogeneous category of clinical entities as defined according to the Diagnostic and Statistical Manual of the American Psychiatric Association, Fourth Edition (DSM IV) (1). The main categories are: (a) bipolar I disorders, (b) bipolar II
disorders, (c) rapid cycling, and (d) bipolar disorders not otherwise specified. To date, there is no unifying model available explaining the underlying psychopathological mechanisms.
