Which patients with major depression benefit from prefrontal repetitive magnetic stimulation

Antidepressive benefit of prefrontal repetitive magnetic stimulation (RTMS) for one or two weeks varies between 6 % and 60 % (mean 37 %) improvement of the Hamilton depression scale vs. 12 % improvement following sham RTMS. This variance is probably caused by study specific stimulus parameters but also by genetic, psychopathological and neuropsychological characteristics of the patients as well as by the functional state of the cortex area below the stimulation coil. Data from 10 open and 7 sham controlled studies including two own studies comprising more than 300 patients with major depression have been published to date. In synopsis several positive predictors for antidepressive response of prefrontal RTMS become apparent: 1) younger age, 2) somatic signs of anxiety, 3) lack of cortical hyperactivity below the magnetic coil pulsed by 10 Hz stimuli, 4) cortical hypermetabolism below the 1 Hz pulsed coil. Negative predictors of response to prefrontal RTMS were: 1) Advanced age, 2) prefrontal atrophy, 3) cognitive impairment in neuropsychological tasks assigned to the prefrontal cortex, 4) psychotic symptoms, 5) cortical hyperactivity below 10 Hz pulsed coil 6) non-response to electroconvulsive therapy (ECT). While prefrontal RTMS will probably not replace ECT in severe major depression with psychotic symptoms it could be beneficial especially in younger anxious patients without cognitive impairment.