Metformin in Co-morbid Diabetes or Prediabetes and Serious Mental Illness

This is a 16 week, double-blind, randomized pilot study, which proposes to recruit 24 patients with schizophrenia, or schizoaffective disorders (DSM 5), who are overweight or obese (BMI >25) and have prediabetes or type 2 diabetes. Randomization occurs on a 2:1 basis, with 16 patients randomised to metformin, and 8 to placebo. Metfomin/placebo is dispensed monthly. The baseline and /or screening visit includes a physical exam (including anthropometric measures), medical history, fasting blood work (glucose, insulin, HbA1c, lipids, electrolytes, thyroid, liver/kidney function), in addition to a urine drug screen. Women of child-bearing age are given a pregnancy test. Patients who meet inclusion criteria and consent to the study have an oral glucose tolerance test (OGTT), and a baseline abdominal and brain MRI (to respectively assess visceral adiposity, a key risk factor for CV disease, and hippocampal volumes). Anthropometric measures and pill counts are repeated bi-weekly. At week 8, fasting insulin/glucose, HbA1C, and liver function tests are measured. End of study measures (week 16), include the same panel of bloodwork conducted at baseline, as well as a repeat OGTT, and an abdominal and brain MRI. Rountine psychopathology scales, including BPRS, CGI, and CDS will be measured at baseline, and week 16. The Brief Assessment of Cognition in Schizophrenia (BACS) will also be completed at baseline, and study end.