Magnetic seizure therapy (MST) shows promise for clinical efficacy with no significant cognitive side effects in patients with treatment-resistant schizophrenia (TRS), according to a recent study published in Frontiers in Psychiatry.
Currently, clozapine is the only treatment indicated for treatment-resistant schizophrenia; however, its use is limited by adverse effects, the need for frequent laboratory analysis, and lack of response in approximately 25% of patients. Electroconvulsive therapy (ECT) has been shown to increase patient response to clozapine, but ECT use is limited by stigma and adverse cognitive effects. The use of repetitive, high-frequency transcranial magnetic stimulation to induce therapeutic seizures in MST may therefore provide benefit for these patients. The electrical current in MST can be directed to avoid the electrical stimulation of the medial temporal lobe, which is believed to cause the cognitive impairments associated with ECT.
Participants were recruited from an open-label MST clinical trial involving patients with a range of serious mental illnesses. Eligible patients had to be diagnosed with schizophrenia, within the age range of 18 to 85 years, suffering moderate to severe symptoms according to the Brief Psychiatric Rating Scale (BPRS), and capable of giving informed consent. Patients were excluded for criteria including pregnancy; metallic implants in the head; recent active substance abuse; and comorbidity with dementia, delirium, or other cognitive disorders. A total of 8 patients were involved in the study, and 4 did not complete treatment. One withdrew after deciding treatment was not working, one withdrew due to anxiety over the treatment procedure, one was removed for missing 3 MST sessions in a row, and one was removed after involuntary hospitalization for a clinical decompensation.
Assessment of participants’ schizophrenia symptoms was performed at baseline, then following every 3 MST sessions. Patients who did not improve by 30% on total BPRS since their previous assessment were given an increase in stimulation duration for their next session. Before and after the treatment phase of the study, cognitive effects were measured using the MATRICS Consensus Cognitive Battery (MCCB) and the short-form Autobiographical Memory Inventory (AMI), and impact on quality of life was measured using the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q).
The patient who withdrew from the study due to anxiety showed BPRS improvement, though not remission. Of the 4 study participants who completed the treatment protocol, 3 achieved remission, and 1 showed no response. The remitters showed quality-of-life improvements and negligible cognitive effects. The only cognitive test to reveal any decline in performance was the AMI, which has been previously called into question because autobiographical recall naturally decreases over short periods of time among healthy adults.
The study investigators believe these preliminary results support the use of MST for patients with treatment-resistant schizophrenia due to the clinically significant improvements demonstrated. The investigators conclude, “To draw more meaningful conclusions about the effect on autobiographical memory, future studies will require a control group to control for the effect of time on autobiographical memory recall.”
Tang VM, Blumberger DM, McClintock SM, et al. Magnetic seizure therapy in treatment-resistant schizophrenia: a pilot study [published January 16, 2018]. Front Psychiatry. doi: 10.3389/fpsyt.2017.00310