Deep brain stimulation (DBS) to different sites allows interfering with dysfunctional network function implicated in major depression.Because a prominent clinical feature of depression is anhedoniaFthe inability to experience pleasure from previously pleasurable activitiesFand because there is clear evidence of dysfunctions of the reward system in depression, DBS to the nucleus accumbens might offer a new possibility to target depressive symptomatology in otherwise treatment-resistant depression. Three patients suffering from extremely resistant forms of depression, who did not respond to pharmacotherapy, psychotherapy, and electroconvulsive therapy, were implanted with bilateral DBS electrodes in the nucleus accumbens. Stimulation parameters were modified in a double-blind manner, and clinical ratings were assessed at each modification. Additionally, brain metabolism was assessed 1 week before and 1 week after stimulation onset. Clinical ratings improved in all three patients when the stimulator was on, and worsened in all three patients when the stimulator was turned off. Effects were observable immediately, and no side effects occurred in any of the patients. Using FDG-PET, significant changes in brain metabolism as a function of the stimulation in fronto-striatal networks were observed. No unwanted effects of DBS other than those directly related to the surgical procedure (eg pain at sites of implantation) were observed. Dysfunctions of the reward systemFin which the nucleus accumbens is a key structureFare implicated in the neurobiology of major depression and might be responsible for impaired reward processing, as evidenced by the symptom of anhedonia. These preliminary findings suggest that DBS to the nucleus accumbens might be a hypothesis-guided approach for refractory major depression. Neuropsychopharmacology (2008) 33, 368-377; doi:10.1038/sj.npp.1301408; published online 11 April 2007 Keywords: deep brain stimulation; major depression; anhedonia; nucleus accumbens; brain stimulation; Cg25
INTRODUCTIONTraditional methods of alleviating depression largely stem from serendipitous observations of antidepressant effects of substances such as iproniazid (originally developed as a treatment for tuberculosis) or imipramine (originally developed as a treatment for schizophrenia). In particular, increasing levels of monoamine neurotransmitters in the synaptic cleft are associated with improvements of depressive symptoms. This insight led to a more targeted drug discovery process, resulting in drugs with fewer side effects, such as SSRIs. These medication treatments, in conjunction with certain methods of psychotherapy and electroconvulsive therapy, are effective at alleviating depressive symptomatology in most patients (Andrews and Nemeroff, 1994;Mann, 2005). However, these treatments do not work for all patients. A sizable minority of patients does not respond. Indeed, twelve percent of patients suffering from major depression have a poor outcome even after 5 years of treatment (Keller et al, 1992). Patien...
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