Use of deep brain stimulation for treatment-resistant depression – review of main stimulation targets

Deep brain stimulation (DBS) is an innovative method using neuromodulation in treatment of various diseases, most commonly used in Parkinson’s disease, tremor and dystonia. Due to method’s minimally invasive nature and very low incidence of severe adverse effects, the research upon its use in other indications is conducted. Treatment-resistant depression (TRD) is one of these emerging indications. Currently available data regarding the matter concentrate mainly of electrode placement within seven particular structures of the brain: the subgenual anterior cingulate cortex, the ventral capsule/ventral striatum, the lateral habenula, the nucleus accumbens, the inferior thalamic peduncle, the bed nucleus of the stria terminalis and the medial forebrain bundle. It is yet to be determined which stimulation targets bring the most optimal effect. Published clinical trials give basis to theorize that stimulation of each DBS target results in different neurotransmitter modulation. Antidepressant effects vary also depending on stimulation parameters and overall duration. The aim of this review is to compare various targets for stimulation and underlying physiological mechanisms in therapy of TRD. It is needed to keep in mind that there is still high demand on well-designed, randomized, double-blind trials on bigger groups of patients in order to exclude potential inconsistency between results of clinical research