Magnetic seizure therapy (MST) is a proposed form of electrotherapy and electrical brain stimulation. It is currently being investigated for the treatment of major depressive disorder, treatment-resistant depression (TRD), bipolar depression, schizophrenia and obsessive-compulsive disorder.^[1][2] MST is stated to work by inducing seizures via magnetic fields, in contrast to ECT which does so using alternating electric currents. Additionally, MST works in a more concentrated fashion than ECT, thus able to create a seizure with less of a total electric charge.^[3] In contrast to (r)TMS, the stimulation rates are higher (e.g. 100 Hz at 2 T) resulting in more energy transfer.^[4] Currently it is thought that MST works in patients with major depressive disorder by activating the connection between the subgenual anterior cingulate cortex and the parietal cortex.^[5]

Magnetic seizure therapy is a new treatment modality that is being studied for the treatment of multiple psychiatric conditions, including major depressive disorder, treatment-resistant depression (TRD), bipolar depression, schizophrenia and obsessive-compulsive disorder.^[1][2]

MST is performed with the use of a modified rTMS device that delivers a higher output.^[7] Similar to ECT, because MST induces seizures, general anesthesia is used to relax the muscles.^[8] However, because there is not an electric current that may stimulate the jaw muscles, a bite block is not necessary.^[8] Coils are placed over the frontal cortex (usually bilaterally) and the treatment dosage is usually determined via titration with a preset dosing schedule.^[3] The treatment dosage is determined once the seizure threshold has been met and a sufficient seizure is produced.^[3] Various coil designs have been tested, such as the figure 8 coil, double cone coil, and cap coil.^[7] The latter two are the ones that have been most reliable in seizure induction.^[7]

The mechanism of action of MST is not yet clearly understood.^[9] One hypothesis focuses on the neuroplasticity of the affected areas of the brain, mostly including the hippocampus and amygdala.^[9] Further recent imaging with fMRI has shown an effect on the connection between the subgenual anterior cingulate cortex and the parietal cortex.^[5]

Adverse effects include disorientation, emergence of mania, and superficial burns due to coil malfunctions.^[10] While one study did note a decline in autobiographical memory after MST, many studies have noted no anterograde memory loss nor retrograde memory loss, both of which are more commonly seen side effects of ECT.^[3][8] Other adverse effects include generalized seizures as well as side effects typically seen with general anesthesia.^[11] Hearing loss is a possible adverse effect from the clicking noise of the magnetic coils if earplugs are not used.^[11]

• Electroconvulsive therapy (ECT)
• Harold A. Sackeim
• Sarah Lisanby