Clinical impacts of single transcranial magnetic stimulation (sTMS) as an add-on therapy in severely depressed patients under SSRI treatment

Research on single and rapid transcranial magnetic stimulation (sTMS/rTMS) indicates an antidepressive efficacy of these methods. In our 4 week study of sTMS, 12 patients affected by severe non-psychotic major depression (DSM-III-R) were enrolled and put on standardized combined antidepressant medication with the serotonin re-uptake inhibitor citalopram, and the serotonin modulating drug, trazodone. They underwent sTMS in a specific method as an add-on therapy. Age, gender, illness and episode duration, episode number, Hamilton Rating Depression Scale-24 (HRDS), Mini-Mental State (MMS), drug levels assessed by HPLC, magnesium and thyroid stimulating hormone (TSH) were recorded. For each patient functional brain imaging was performed by (18)FDG and (99m)Tc HMPAO SPECT at the beginning of the study, as were EEG tracings which also were recorded at the end. Lorazepam was allowed as co-medication. Of the patients, 66.7 per cent (N=8) could be identified as sTMS responders. Possible predictors for sTMS response as add-on therapy may be duration, pattern of improvement in global and in specific single items of the HRDS, lorazepam dosage, functional involvement of basal ganglia and cortical temporal lobe and the initially lower mean frequency and lability of the alpha-activity of EEG. These variables possibly predict the clinical outcome of depressed patients treated by sTMS as an add-on therapy.