Magnetic seizure therapy (MST) for major depressive disorder

Abstract

Electroconvulsive therapy (ECT) is effective for major depressive disorder (MDD) but its effects on memory limit its widespread use. Magnetic seizure therapy (MST) is a potential alternative to ECT that may not adversely affect memory. In the current trial, consecutive patients with MDD consented to receive MST applied over the prefrontal cortex according to an open-label protocol. Depressive symptoms and cognition were assessed prior to, during and at the end of treatment. Patients were treated two to three times per week with high-frequency MST (i.e., 100 Hz) (N = 24), medium frequency MST (i.e., 60 or 50 Hz) (N = 26), or low-frequency MST (i.e., 25 Hz MST) (N = 36) using 100% stimulator output. One hundred and forty patients were screened; 86 patients with MDD received a minimum of eight treatments and were deemed to have an adequate course of MST; and 47 completed the trial per protocol, either achieving remission (i.e., 24-item Hamilton Rating Scale for Depression score <10 and a relative reduction of >60% at two consecutive assessments; n = 17) or received a maximum of 24 sessions (n = 30). High-frequency (100 Hz) MST produced the highest remission rate (33.3%). Performance on most cognitive measures remained stable, with the exception of significantly worsened recall consistency of autobiographical information and significantly improved brief visuospatial memory task performance. Under open conditions, MST led to clinically meaningful reduction in depressive symptoms in patients with MDD and produced minimal cognitive impairment. Future studies should compare MST and ECT under double-blind randomized condition.

Magnetic Seizure Therapy for Suicidality in Treatment-Resistant Depression

“…Thus, we explored the association of MST with suicidality in a secondary analysis of a recently published open-label study on MST for TRD. 22 We hypothesized that MST would be associated with clinically meaningful rates of remission from suicidality as measured by the Beck Scale for Suicidal Ideation (SSI). We also explored whether the association of MST with suicidality differed among different MST stimulation frequencies in a sensitivity analysis.…”

“…In the original study, 22 baseline suicidality, as defined by a score greater than 0 at the initial study visit on the Beck SSI, a validated 19-item scale used to quantify suicidality with a range from 0 to 38. 26 The main analyses in the present report focus on the 67 participants with baseline suicidality who were defined as adequate trial completers in that they completed at least 8 MST sessions.…”

“…Participants received MST using the MagPro MST device with Twin Coil-XS (both from MagVenture) applied over the frontal cortex at 100% machine output with low (25 Hz), moderate (50 or 60 Hz), or high (100 Hz) frequency.These frequencies were chosen for participants in an open-label fashion in consecutive treatment cohorts (ie, there was no randomization for treatment groupings). Please refer to the original report for further details of treatment procedures 22.…”

Subgenual cingulate connectivity and hippocampal activation are related to MST therapeutic and adverse effects

“…The activation of the Hipp during ECT is hypothesized to be associated with the treatment related cognitive side effects 30,35,36 . MST treatments appear to have only minimal if any cognitive side effects 34 . The lack of cognitive side effects after MST is believed to be related to the focality of the induced effective field during stimulation 63 .…”

“…MST is a novel seizure inducing, neuromodulatory treatment for MDD with a similar efficacy as ECT [31][32][33] . By contrast, a large MST clinical trial that included an extensive cognitive battery found that MST had only minimal impact on autobiographical memory consistency 34 . The lack of cognitive side effects after MST is believed to be related to the focality of the induced effective field, and the sparing of hippocampal direct activation during treatment 30,35,36 .…”