Deep brain stimulation of the subcallosal cingulate gyrus in the treatment of treatment resistant depression

Objective: a systematic review to determine the efficacy of deep brain stimulation (DBS) targeting the subcallosal cingulate gyrus (SCG) for the treatment of treatment resistant depression (TRD). Methods: PubMed database was utilized in a search for clinical randomized control trials that were completed after the year 2000, using the terms deep brain stimulation, treatment resistant depression, and subcallosal cingulate gyrus. Results: Three clinical trials were chosen based on specific inclusion criteria as noted in the PRISMA flow chart (Chart 1). The results of the three articles showed various discrepancies. Two of the three studies demonstrated some statistical significance in reduction of scores on the Hamilton Depression Rating Scale (HAM-D). However, in one study, the significance was seen only after long term therapy of over a year compared to 8 weeks of treatment (df(4); F = 10.691; P = 0.031). The other study showed that treatment was effective after a 6-month study with significantly higher HAMD-17 scores during SHAM versus active stimulation (χ21 = 5.0, p= 0.025). On the other hand, the last study did not demonstrate any statistical significance after a 6 months double blinded controlled phase and 6 months open label trial (p\u3c 0.05), with scores based on the Montgomery–Åsberg Depression Rating Scale (MADRS) rating scale. However, unlike results from the MADRS scale, utilization of the Global Assessment of Function score did demonstrate statistical significance after both phases of the trial. Conclusion: In summary this systematic review demonstrated that DBS of the SCG shows minimal weak evidence in overall effectiveness of treating treatment resistant depression. Although it is efficacious in some, current data fails to show consistent statistical significance throughout studies and therefore further research should be completed prior to utilizing DBS of the SCG as the main treatment for TRD. At this point in time and until further research is done, it is difficult to state whether or not we would recommend the use of DBS to treat TRD