A recent study by Kishi and Iwata examined the effects of varenicline for smoking cessation in people with schizophrenia in a meta-analysis of seven randomised controlled trials.68 With the exception of the study by Hong and colleagues,69 we included all their randomised controlled trials in the current analysis. Similar to our findings, Kishi and Iwata found no significant differences in depression and suicidal ideation between the varenicline and placebo groups. They reported, however, that varenicline use was associated with a lower risk of abnormal dreams/nightmares than placebo (relative risk 0.47, 95% confidence interval 0.22 to 0.99; P=0.05).68 This discrepancy with our findings could be explained by the small sample size of their study (288 from four randomised controlled trials versus 10 347 from 35 randomised controlled trials in our analysis).
