Double-Blind Trial of a Probiotic Supplement to Reduce the Symptoms of Schizophrenia

The primary aim of the current study is:

1. To evaluate the safety and efficacy of a supplemental probiotic therapy, containing the
microorganisms Lactobacillus rhamnosus GG and Bifidobacterium lanimalis subsp. lactis
(BB12), for individuals with schizophrenia who have residual psychotic symptoms of at
least moderate severity.

Secondary aims of the study are:

2. To assess the effect of probiotic treatment on patients' gastrointestinal functioning

3. To study the effect of probiotic treatment in lowering the levels of antibodies to
casein and gliadin.

4. To investigate the association between the efficacy of probiotic therapy and initial
levels of antibodies to gliadin and casein.

Inclusion Criteria:

- Age 18-65.

- Capacity for written informed consent.

- Primary Axis I diagnosis (DSM-IV) of schizophrenia, any type, OR schizoaffective
disorder (APA, 1994).

- Currently an outpatient at the time of enrollment.

- Residual psychotic symptoms which are at least moderately severe as evidenced by one
or more PANSS positive symptom scores, and/or PANSS negative symptom scores of 4 or
more; OR a total PANSS score of 50 or more, containing at least three positive or
negative items with scores of 3 or more at screening.

- Conformance to PORT Treatment Recommendation re Maintenance Antipsychotic Medication
Dose (Buchanan et al., 2010).

- 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:

- Diagnosis of mental retardation.

- Any clinically significant or unstable medical disorder as determined by the
investigators, including congestive heart failure, abnormal liver function or disease,
renal failure, acute pancreatitis, any diagnosis of cancer undergoing active
treatment, HIV infection or other immunodeficiency condition.

- History of IV drug use.

- Primary diagnosis of substance abuse or dependence according to DSM-IV criteria within
the last three months.

- 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 previous 14 days (as anaerobic organisms
residing in the gastrointestinal tract may be minimally affected by antibiotics).

- Documented celiac disease (as such persons should be on a gluten-free diet as this is
the standard care).

- Of note, the investigators are not limiting the study to individuals with elevated
levels of gliadin or casein antibodies as the investigators intend to look at these
levels as a predictor of response.