In this study, a patient with treatment resistant depression, as defined by Harold Sackeim, is subjected to 5 weeks of treatment with active or sham PEMF treatment for 30 minutes on every working day. The pharmacological treatment for depression is maintained unaltered throughout the study. Depression severity is measured at the beginning of the study and at each weekly visit. Side effects are closely observed. The ability to concentrate is measured by the AQT test (Alzheimers Quick Test). Personality is assessed by use of the SCID-II-instrument (DSM-IV axis II).