Synbiotic Compound to Reduce Symptoms of Schizophrenia

Inclusion Criteria:

* Age 18-65, inclusive.
* Capacity for written informed consent.
* Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) diagnosis of schizophrenia or schizoaffective disorder (APA 2013) as determined by the Structured Clinical Interview for DSM-5 Disorders (SCID-5).
* Outpatient at the time of enrollment.
* Residual psychotic symptoms of at least moderate severity as evidenced by a Positive and Negative Syndrome Scale (Kay et al., 1987) (PANSS) total score of 60 or higher AND one or more of the following: one or more PANSS positive symptom scores of 4 or higher; OR containing at least three positive or negative items with scores of 3 or higher at the screening visit.
* Receiving antipsychotic medication for at least 8 weeks prior to starting the study with no medication changes within the previous 21 days.
* Proficient in the English language.

Exclusion Criteria:

* DSM-5 diagnosis of intellectual disability or comparable diagnosis determined by previous versions of the DSM.
* Any clinically significant or unstable medical disorder as determined by the investigators, including congestive heart failure, liver disease, renal failure, any diagnosis of cancer undergoing active treatment.
* A primary immunodeficiency condition such as HIV infection, or undergoing cancer chemotherapy, or receiving systemic corticosteroids, methotrexate or monoclonal antibodies for treatment of an autoimmune disorder.
* History of IV drug use.
* DSM-5 diagnosis of a moderate or severe substance use disorder, except for caffeine or tobacco, within the last three months prior to the screening visit. If the patient has a positive drug toxicity screen at the time of visit 1 (screening) further evaluation by the investigator will be done of the substance use to determine eligibility.
* Participated in any investigational drug trial in the past 30 days.
* Pregnant or planning to become pregnant during the study period.
* Receipt of antibiotic medication within the 14 days prior to visit 2 (as anaerobic organisms residing in the gastrointestinal tract may be minimally affected by antibiotics). Of note, patients on antibiotic may be re-screened once the minimum duration of time since antibiotics use has been met.
* Current and regular use of a probiotic and or prebiotic supplement within the past 2 weeks. Of note, patients taking prebiotic or probiotic supplements may be re-screened.
* Documented inflammatory bowel disease (e.g. Crohn's disease or ulcerative colitis) or celiac disease