Repetitive Transcranial Magnetic Stimulation for Smokers with Schizophrenia: A Systematic Review and Meta-analysis of Six Randomized Controlled Trials

Abstract Aims A systematic review and meta-analysis was conducted to evaluate the effects of repeated transcranial magnetic stimulation (rTMS) on smokers with schizophrenia. Methods Only Randomized Controlled Trials (RCTs) with rTMS on smokers with schizophrenia were included. The risk of bias of the included studies were assessed using Cochrane Risk of Bias tool. Outcome indicators include changes in smoking behavior, psychiatric symptoms, and depressive symptoms. The meta-analysis was performed using RevMan 5.3 software. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system was used to evaluate the quality of the evidence. Findings Six RCTs involving 571 smokers were included. The methodological quality results showed that two RCTs were assessed as high risk of bias, three were low, and seven were unclear. The meta-analysis showed that, comparing with sham rTMS, active rTMS significantly decreased the average daily number of cigarettes smoked (6 trials, MD = -8.50, 95% CI [-11.93, -5.06], very low quality) and the FTND score (4 trials, MD= -2.71, 95% CI [-3.22, -2.21], high quality). Meanwhile, rTMS improved the general psychiatric symptoms score (4 trials, MD= -1.89, 95%CI [-3.32, -0.47], moderate quality), and did not relieve the depressive symptoms score (2 trials, MD=-2.90, 95% CI [-8.72, 2.93], P = 0.33, very low quality). Conclusions rTMS might provide effective support for smokers with schizophrenia. It could reduce the craving for tobacco and might improve psychological symptoms. However, this conclusion needs more research and high evidence to support.