C.Y.Z.TANG1, Y.C.CHUA1, J.H.TEO1, E.ABDIN1, M.SUBRAMANIAM1, S.K.VERMA1
Institute of Mental Health1
Excessive weight gain and cardiometabolic dysfunction are common and clinically relevant side effects of antipsychotic medications. In this pilot study, we aimed to establish the feasibility of metformin and its effectiveness in managing antipsychotic-induced weight gain in patients with first episode psychosis (FEP) on follow-up with the Singapore Early Psychosis Intervention Programme (EPIP) through a 24-week randomized double-blind placebo-controlled trial, ascertain the effects of metformin discontinuation on body weight, and evaluate the safety and tolerability of metformin.
Participants between the ages of 16 and 40 with a FEP disorder were recruited from EPIP outpatient clinics between April 2015 and April 2018. Participants had to be assessed as clinically stable and to have gained ≥5% of their pre-drug weight after initiation of antipsychotic treatment. Enrolled participants were randomized into either the metformin or placebo arm at Week 0, with follow up assessments at Weeks 3, 6, 12, 24 and 36. Seventeen participants met all inclusion criteria and was randomised to receive either metformin (n=8) or placebo (n=9).
Participants in the metformin arm were associated with significantly better weight control than the participants in the placebo arm, an effect that did not persist after discontinuation.
Metformin was generally well tolerated with only mild gastrointestinal side effects. Our results support the use of metformin as a safe and tolerable weight control measure in a typical outpatient sample of young people with FEP.