The Effects of Prebiotics on Cognitive Functioning and Weight Gain in Psychosis
Condition: Schizophrenia
MeSH terms: Schizophrenia
Study type: Interventional

Summary: 
      The investigators propose a maltodextrin-controlled cross over experimental medicine study
      that aims to examine the role of the immune system in cognitive processes and weight gain in
      40 adult patients with psychosis, stable on antipsychotic medication for over 1 month. There
      is evidence suggesting the immune system is linked to brain function and weight gain, both
      parameters that has been implicated in psychosis and antipsychotic use, and may underlie some
      schizophrenic features. The fermentation of galacto-oligosaccharides (GOS), which are short
      chain carbohydrates composed mostly of galactose sugar molecules, by the intestinal
      microbiota has been shown to modulate the immune system and reduce the inflammatory response
      in both animals and humans. Since the intestinal ecosystem is highly sensitive to dietary
      changes, the growth of beneficial gut bacteria can be enhanced using a natural food
      supplement similar to GOS known as prebiotics. The study will be controlled by taking
      maltodextrin as a control supplement. Both prebiotics and maltodextrin are short chain sugar
      compounds. The study will involve asking patients to take dietary supplement for a total of
      24 weeks; GOS for 12 weeks and maltodextrin for 12 weeks as a control. Participants will be
      randomised into groups, with half receiving maltodextrin followed by GOS, and half receiving
      GOS followed by maltodextrin. Participants will be assessed on cognitive function and weight
      gain at 3 specified time points.
    

Detailed description: 
      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.
    

Intervention name(s): prebiotics; Maltodextrin
Intervention type(s): Dietary Supplement; Dietary Supplement
Intervention description(s): Bimuno (BGOS): The active supplement of the food supplement (Bimuno) used in this study is called galacto-oliogosaccharides (Bimuno®, BGOS). BGOS is a compound metabolised by specific bifidobacteria, which are beneficial bacteria, in our colon. Bimuno (2.3 calories) is composed by the following ingredients per gram of Bimuno: 0.96g dry matter; <01g Fat; <0.06g Protein; 0.821g GOS; 0.119g Lactose; 0.0331g Glucose and 0.0029g Galactose. Bimuno is tasteless. Bimuno will be supplied in coded sachets (3.5g) for dispensing by parents. Each participant will be required to consume 1 sachet daily during breakfast, by mixing it with food or in a drink.; Maltodextrin is a polysaccharide in powder form, which grows most bacteria in the gut, and not specifically the beneficial bifidobacteria. The placebo will also be provided in daily coded sachets (3.5g) for dispensing by parents. Each participant will be required to consume 1 sachet daily during breakfast, by mixing it with food or in a drink. This placebo has been used in previous studies, in which Bimuno was used as the active intervention. The placebo will be similar in taste and colour to the active intervention.
Other intervention name(s): Bimuno® galacto-oliogosaccharides (BGOS)
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: 24 week cross-over at 12 week involving preiotics and maltodextrin
Masking: Double (Participant, Investigator)
Primary purpose: Other
Keywords: prebiotics; cognitive impairment; weight gain