Effects of rTMS on cognitive and negitive symptoms of schizophrenia: A randomized double-blind sham-controlled study

Background Investigators are urgently searching for options to treat cognitive and negative symptoms in schizophrenia because these symptoms are disabling and do not respond adequately to antipsychotic or psychosocial treatment. This study evaluated the efficacy of 20-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left dorsolateral prefrontal cortex for the treatment of cognitive and negative symptoms in schizophrenia. Methods The study was a randomized double-blind sham-controlled trial for 4 weeks. Seventy patients with schizophrenia were randomly assigned into two treatment groups. After a 2-week pretreatment phase, 34 patients were treated with 20-Hz rTMS applied 5 days per week for 4 weeks to the left dorsolateral prefrontal cortex (added to the ongoing treatment), and 33 patients were subjected to sham rTMS applied similarly. Negative symptoms were assessed with the Scale for the Assessment of Negative Symptoms (SANS), the Positive and Negative symptom scale (PANSS), and Cognitive symptoms were assessed by MATRICS cognitive test battery (MCCB) Chinese version. Results Sixty patients (33 individuals in active group and the other 27 in the sham group) completed the treatment protocol. We found that treatment with 20-Hz rTMS for 4 weeks significantly improved negative symptoms in the active group as compared to the sham group. However, There was no statistically significant difference in improvement in cognitive symptoms between the two groups. Conclusions These findings indicate that application of 20-Hz rTMS to the left dorsolateral prefrontal cortex can effectively improve the negative symptoms, while more optimized parameters are needed to achieve improved therapeutic efficacy for the treatment of cognitive symptoms.