The objectives of the study are to examine the gut microbiome composition and diversity in patients with schizophrenia, schizoaffective disorder, or other specified schizophrenia spectrum and other psychotic disorder at 6 weeks and 3 months post antipsychotic initiation. Furthermore, the team aims to investigate causality of antipsychotic (AP)-induced changes in the GMB in relation to metabolic changes. This will be accomplished by transplanting human gut microbiota from patients initiating an AP treatment into germ-free mice (independent animal protocol). The final objective is to observe changes in cognition associated with changes in metabolic factors and gut microbiome.
The hypotheses of the study are twofold: the primary hypothesis is that there will be changes in the gut microbiome overtime with treatment correlated with metabolic measures (i.e. weight, insulin sensitivity, glucose tolerance, lipids) due to treatment in antipsychotic naïve patients, and the gut microbiome of treated patients transplanted into germ-free mice will induce similar metabolic proving causality (separate animal protocol). The secondary hypothesis is that APs will produce changes psychopathology and cognitive outcome measures which will correlate with changes in gutmicrobiome.
Participants will include individuals who are either antipsychotic naïve or have not taken antipsychotics for at least 3 months prior to study participation. Participants will be between 12 and 35 years of age with a diagnosis of schizophrenia, schizoaffective disorder, or other specified schizophrenia spectrum and other psychotic disorder, as per DSM-V criteria. Participants will be enrolled to reach n=25 complete data sets. Participants who drop out or who are withdrawn will be replaced.
Following provision of written informed consent, participants will be assessed for suitability for inclusion in the study based on the inclusion and exclusion criteria. Participants will be seen across 5 timepoints, including a screening and baseline visit, as well as 3 follow-up appointments.
Within-group analyses will be conducted to evaluate changes in participants at different time points on measures including anthropometric measures, clinical scales, and fasting bloodwork results. Microbiome analysis will include α-diversity metrics for each sample and β-diversity measures (weighted and unweighted unifrac, Specifically we will analyze changes in the microbiome pre- and post- antipsychotic treatment and whether changes in the microbiome associate with other clinical and biochemical measures. We will also determine whether patients that develop metabolic side effects with antipsychotic treatment have different microbial profiles than those who do not develop these side effects.
Whole body insulin sensitivity is calculated based on the original description by Matsuda at baseline and endpoint. HOMA-IR will be calculated at baseline, week 6, and week 12 to determine change in insulin resistance over time.
A blood sample will be collected for DNA extraction to examine for the genes that that are hypothesized to be associated to response or side effects following antipsychotic medication. Fecal DNA analyses will be completed at McMaster University. Stool samples will be collected from participants at baseline, weeks 3 and 6. Participants will be given stool collection kits (OMNIgene•GUT, DNA Genotek Ottawa, ON). Participants will return the sample at their earliest convenience. Once returned, samples will be immediately frozen and stored at -80°C.
