Continuation Magnetic Seizure Therapy for Treatment-Resistant Unipolar or Bipolar Depression

Objective: Electroconvulsive therapy (ECT) is highly effective for treatmentresistant depression (TRD) but may be associated with adverse cognitive effects. Magnetic seizure therapy (MST) is a promising alternative convulsive treatment with a safer cognitive profile. Although there is emerging evidence for the efficacy of MST for TRD as an acute treatment, there are no published studies of continuation MST for the prevention of relapse. Methods: Patients with TRD with a DSM-IV diagnosis of major depressive disorder or bipolar disorder who met response criteria after acute MST were offered continuation MST in a prospective, open-label trial between February 2012 and June 2019. They received 12 continuation MST sessions with decreasing frequency over the course of 6 months, with additional booster sessions if their depression symptoms started to worsen. The primary outcome was relapse of depression or psychiatric hospitalization. Secondary outcomes included relapse of suicidal ideation and neurocognitive outcomes. Results: Thirty participants completing at least one assessment during continuation MST were included in the analysis; 10 (33.3%) relapsed, with no significant differences in survival distributions between unipolar and bipolar groups (χ2 = 0.3, P = .58). Mean (SD) survival time was 18.6 (1.6) weeks. All 17 participants who achieved resolution of baseline suicidality after acute MST remained free of suicidality during the continuation phase. Except for improvement in verbal fluency, neurocognitive test scores did not change during continuation MST. Conclusions: During 6 months of continuation MST, two-thirds of participants sustained improvements in depressive symptoms without any adverse cognitive effects. Future studies of continuation MST are warranted, particularly in comparison to ECT.