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The correct answer is B.
DBS involves MRI-assisted electrode implantation directly into brain regions associated with mood. The procedure takes 3 to 6 hours and is done under a combination of local and general anesthesia. Multiple brain targets have been tested in clinical trials, all with similar effects, which suggests that they may all be nodes in a common “mood regulation” network.1 DBS has only been tested in patients who no longer respond to any other therapy.
Initially, DBS patients report “disappearance of the void,” reduced anxiety, increased connectedness, and euphoria, subjective changes that usually fade within minutes to hours. Continued stimulation over weeks to months leads to more gradual improvement. In early open label studies, response rates were 40% to 66% in severely treatment-refractory cases.2,3 When it is effective, the benefits appear to last—a recent study reported over 50% response rate at 8 years post-DBS.4
Risks include intracranial bleeding, stroke, seizure, and infection, but all are very rare (less than 1%). Adverse psychological effects are more common—up to 50% of patients may experience worsened mood, anxiety, or hypomania while their clinicians search for optimal stimulation settings. Furthermore, patients often see DBS as a last resort.
1. Widge AS, Malone DAJ, Dougherty DD. Closing the loop on deep brain stimulation for treatment-resistant depression. Front Neurosci. 2018;12:175.
2. Mayberg HS, Lozano AM, Voon V, et al. Deep brain stimulation for treatment-resistant depression. Neuron. 2005;45:651-660.
3. Malone DA, Dougherty DD, Rezai AR, et al. Deep brain stimulation of the ventral capsule/ ventral striatum for treatment-resistant depression. Biol Psychiatry. 2009;65:267-275.
4. Crowell AL, Riva-Posse P, Holtzheimer PE, et al. Long-term outcomes of subcallosal cingulate deep brain stimulation for treatment-resistant depression. Am J Psychiatry. 2019;176:949-952.
For more on this topic, see Neuromodulation Approaches to Mood Disorders, on which this quiz is based.