ABSTRACT
INTRODUCTIONDeep brain stimulation (DBS) has emerged as an alternative, reversible, nonablative neuromodulatory treatment for severely refractory major depressive disorder (MDD) and bipolar depression (BD). In the past decade, DBS for mood disorders has been reported in small case series, and it remains largely investigational. For those patients who do not receive therapeutic benefit from other available treatment options, including pharmacotherapy, psychotherapy, and electroconvulsive therapy, DBS holds promise [1, 2]. In general, DBS is believed to work by modulating the cortico-striato-thalamo-cortical (CSTC) circuits (see Fig. 11.1). The CSTC and its associative limbic and motor circuits have been implicated in the pathogenesis of MDD and BD. Various DBS targets have been examined for treatment-resistant depression
(TRD) including the subgenual cingulate gyrus, ventral capsule/ventral striatum, nucleus accumbens, inferior thalamic peduncle, lateral habenula and the medial forebrain bundle. Still, many important clinical questions remain, including: (1) what is the most appropriate, effective and therapeutically consistent target, (2) what are the optimal stimulation parameters, and (3) what are the progressive mechanisms of action and how can recovery be optimized over time? This chapter will review reported clinical trials of DBS for MDD and BD, describing rationale for target selection, reported efficacy, clinical applicability and hypothesized mechanisms of action.
