Microbiota Modulation for Psychiatry Patients

The investigators aim to confirm pilot study findings (REB 119638) on the effects of delayed release apple cider vinegar (drACV). The investigators aimed to determine the feasibility that the acetate in ACV would counteract the problematic weight gain and metabolic side effects associated with the most common psychiatric medications. Our pilot study recruited 11 participants from the First Episode Mood and Anxiety Program (FEMAP) who had experienced (by self-report) weight gain concurrent with medication use. The investigators found that drACV was well tolerated with adherence above 90% and resulted in reduced LDL cholesterol, improved lipids in 7 participants, altered microbiota composition in the direction associated with improved metabolic and mental health outcomes, and the emergence of a potential \"responder phenotype\". The investigators did not, however, find significant effects on weight. The investigators aim to expand that study by 1) including a larger sample; 2) Conducting a detailed analysis of the microbiome and identifying immune and genomic factors associated with response, thereby further defining responder and non-responder phenotypes that emerged in the initial analysis, 3) collecting additional biological, psychological, and social data to permit complex multivariate modelling on gene-environment interactions for mechanistic research. The investigators will seek to recruit sixty-two participants from FEMAP, the General Adult Ambulatory Mental Health Services (GAAMHS) and Child and Adolescent Mental Health Services at LHSC. Participants need to have experienced weight gain by self-report and clinician estimation, be psychiatrically stable on steady doses of medication, and be between the ages of 16-45.