Superolateral medial forebrain bundle deep brain stimulation in major depression: a gateway trial

Area of Science:

• Neuroscience
• Psychiatry
• Neurosurgery

Background:

• Deep brain stimulation (DBS) has shown antidepressant potential in treatment-resistant depression (TRD).
• Previous randomized trials for other targets failed, necessitating careful study design.
• The supero-lateral branch of the medial forebrain bundle (slMFB) is a potential target for DBS in TRD.

Purpose of the Study:

• To assess the efficacy and safety of DBS targeting the slMFB in a Phase I clinical study.
• To gather data for planning a larger randomized controlled trial (RCT) for slMFB-DBS in TRD.
• To evaluate the onset and stability of antidepressant effects.

Main Methods:

• A small Phase I study involving 16 patients with TRD receiving DBS of the slMFB.
• Patients were randomized to sham or real stimulation for 2 months post-implantation.
• Primary outcome: Mean reduction in Montgomery-Åsberg Depression Rating Scale (MADRS) over 12 months; secondary outcomes: clinical measures comparing sham vs. real stimulation.

Main Results:

• Significant MADRS reduction from baseline (29.6) to 12.9 over 12 months of DBS.
• All patients achieved response criteria, with 50% achieving remission after 1 year.
• Transient strabismus was the most frequent side effect; both groups showed a micro-lesioning effect, with additional benefit from active stimulation.

Conclusions:

• slMFB-DBS demonstrated rapid onset and stable antidepressant effects in TRD patients.
• The findings support the potential of slMFB-DBS and provide crucial data for designing future large-scale RCTs.
• Adaptive study development, including meaningful comparisons and timeline analyses, is vital for DBS trials in severe psychiatric conditions.