The Effects of Prebiotics on Cognitive Functioning and Weight Gain in Psychosis

An 24-week maltodextrin-control cross-over experimental medicine study enrolling 40 patients with psychosis. Participants will receive a 12-week treatment with Bimuno™ GOS, as well as a 12-week maltodextrin supplement. The order of supplements that participants will receive is randomized. A washout period was considered unnecessary as maltodextrin is an inactive placebo wherein negligible effects have been shown on bifidobacteria growth, and therefore, would present with no carryover/lasting effects to mask the prebiotic effect. Eligible patients will be invited to be screened for the study and assessed to ensure they meet inclusion/exclusion criteria. If the participant passes this initial screening stage and conditional to informed consent, he/she will then be randomized into one of the two groups. Once decided, the participant will be assessed by a research assistant using standard clinical assessments used to diagnose/evaluate cognitive deficits. A 12-week supply of sachets containing prebiotic or maltodextrin will be provided for the participant to allow participants to complete the first quarter of the study. Additional 12-week supplies of prebiotics or maltodextrin will be provided at the study follow-up. Since clozapine/olanzapine are well known antipsychotics that induce weight gain and interfere with the immune system an additional sub-analysis of those participants stable on clozapine/olanzapine will be performed, contingent on the demographics. The study will include five sessions in total all taking place at either University Department of Psychiatry, Warneford Hospital, or a location convenient to the participant (e.g., patient home): (1) screening session, (2) baseline cognitive and blood measurements, (3) study follow up, and (4) final testing session.