We have made a 2-year follow-up study to evaluate the effect of repeated transcranial pulsating electromagnetic fields (T-PEMF) augmentation in patients who had achieved remission but later on relapsed, as well as to identify factors contributing to treatment-resistant depression in patients who did not respond to T-PEMF.

Using the Longitudinal Expert Assessment of All Data approach the patients were classified in four groups: A: patients who achieved remission; B: patients with doubtful effect; C: patients with no effect; and D: patients who were hard-to-assess.

In group A, comprising 27 patients, 13 had relapsed; they obtained a clear remission after a repeated course of T-PEMF augmentation. In group D, comprising 16 patients, we identified misdiagnostic factors both concerning the event of remission after the previous T-PEMF augmentation and concerning the aetiology (psychosocial stressors and co-morbid conditions). Compared with the other groups, the group D patients had a smaller number of previous episodes (p=0.09) and a longer duration of the current episode (p=0.01).

T-PEMF has an effect among patients who relapsed after remission with the first series of T-PEMF. Treatment-resistant depression is a condition that has a high degree of multivariate problems. Misuse of alcohol or drugs, severe somatic disorders and other psychosocial problems may need other kinds of treatment before T-PEMF augmentation.

The aim of this study was to evaluate the predictive validity of the apathy subsyndrome in patients with therapy-resistant depression in the dose–remission study with transcranial pulsating electromagnetic fields (T-PEMF).

The apathy subsyndrome consists of the symptoms of fatigue, concentration and memory problems, lack of interests, difficulties in making decisions, and sleep problems. We evaluated 65 patients with therapy-resistant depression. In total, 34 of these patients received placebo T-PEMF in the afternoon and active T-PEMF in the morning, that is, one daily dose. The remaining 31 patients received active T-PEMF twice daily. Duration of treatment was 8 weeks in both groups. The Hamilton Depression Scale (HAM-D17) and the Bech-Rafaelsen Melancholia Scale (MES) were used to measure remission. We also focused on the Diagnostic Apathia Scale, which is based on a mixture of items from the MINI and the HAM-D17/MES.

In patients without apathy, the remission rate after T-PEMF was 83.9% versus 58.8% in patients with apathy (p≤0.05). In patients without apathy receiving one active dose daily 94.4% remitted versus 50% for patients with apathy (p≤0.05). In patients without apathy who received two active doses 69.9% remitted versus 66.7% for patients with apathy (p≤0.05).

Taking the baseline diagnosis of the apathy syndrome into consideration, we found that in patients without apathy one daily dose of T-PEMF is sufficient, but in patients with apathy two daily doses are necessary. Including the apathy syndrome as predictor in future studies would seem to be clinically relevant.