RTMS in resistant mixed states: An exploratory study

Background Repetitive transcranial magnetic stimulation (rTMS) has shown efficacy in resistant unipolar depression, but its efficacy in bipolar disorders has not yet been extensively investigated. Mixed episodes are reported in up to 40% of acute bipolar admissions and are associated with severe psychopathology, comorbidity, high risk of suicide and poor treatment response. Right low-frequency rTMS (LF-rTMS) as an augmentation treatment might be effective for mixed states. Methods Forty patients were treated during a 4-week period with a mood stabilizer and subsequent rTMS (low frequency stimulation - 1 Hz - applied to the right Dorso-Lateral Prefrontal Cortex (DLPFC)) as add-on treatment for 3 weeks. Response to LF-rTMS was assessed by the Hamilton Depression Rating Scale (HAM-D), the Young Mania Rating Scale (YMRS) and the Clinical Global Impressions-Bipolar Version (CGIBP) subscales. ANOVA with repeated measures performed on HAM-D, YMRS and CGI-BP subscales "change from the preceding phase" and "severity of illness" showed a statistically significant time effect from the baseline to the endpoint. Results For the HAM-D there was a 46.6% responder rate, of which 28.6% was remitted, while for the YMRS there was a 15% responder rate, all of which was remitted. Limitations The open label-design of our study and the lack of a sham-controlled group represent a methodological limitation. Conclusions The results suggest that LF-rTMS on the right DLFC might be a potential augmentation strategy in the treatment of both depressive and manic symptoms in mixed states.