Objective: Despite the development of second-generation antipsychotic drugs, treatment-resistant symptoms still represent a serious problem in schizophrenia. The aim of the present article was to review studies with repetitive transcranial magnetic stimulation for negative symptoms of schizophrenia and draw conclusions for clinical decision making.
Method: Literature for this review was identified by searching MEDLINE and ISI Web of Science up to the year 2011.
Results: Five open studies, 13 sham-controlled studies, and 2 meta-analysis and 2 review articles were included in the present paper. The effect size of the high frequency repetitive transcranial magnetic stimulation (rTMS) over the left prefrontal cortex in the treatment of negative symptoms of schizophrenia is thought to be mild to moderate (Cohen d = 0.43–0.68).
Conclusion: Despite the promising results of some rTMS studies, the potential of rTMS for the treatment of negative symptoms is currently relatively unclear. Large clinical studies are therefore needed, especially large multicentric studies such as depression rTMS studies.
* There is an evidence showing that rTMS can be considered the effective treatment option for negative symptoms of schizophrenia.
* Based on the results of current meta-analyses, the effect size of high-frequency rTMS in the treatment of negative symptoms of schizophrenia seems to be mild to moderate (Cohen d = 0.43–0.63).
* Despite limited evidence base, the associations between efficacy and stimulation approaches (higher stimulation intensity, higher number of sessions or 10 Hz stimulus frequency) appear.
* Neither the European Medicines Agency nor the Food and Drug Administration has approved rTMS for the treatment of negative symptoms of schizophrenia.
* Furthermore, large clinical studies are necessary to verify the natural benefit of rTMS for general clinical practice.