Metformin reduces 12-month change in body weight among people newly commenced on clozapine: a retrospective naturalistic cohort study.

In this small retrospective cohort study, use of metformin within 12-months of clozapine initiation was associated with a statistically and clinically significant reduction in CIWG. Although there is increasing evidence for the role of metformin to ameliorate bodyweight gain at time of clozapine initiation, our findings need replication and testing in a randomised controlled trial before recommending metformin co-commencement with clozapine as standard clinical practice.