The purpose of this study is to determine if taking a probiotic supplement versus a placebo will lower rates of relapse and improve the clinical course among participants who have been hospitalized for mania. Relapse and clinical course are measured by time to re-hospitalizations, new mood episodes, and changes in mood-related symptoms.

Inclusion Criteria:

• Age 18-65
• Capacity for written informed consent
• Currently admitted to a Sheppard Pratt inpatient or day hospital for symptoms of mania
• Primary Axis I diagnosis (DSM-IV) at time of admission of Bipolar I Disorder (single manic episode, most recent episode manic, or most recent episode mixed) OR Schizoaffective Disorder, Bipolar type (manic or mixed state)
• Proficient in the English language
• Available to come to Sheppard Pratt Towson for follow-up visits
• Participated previously in one of our screening studies

Exclusion Criteria:

• Diagnosis of mental retardation
• Symptoms of mania secondary to a general medical condition
• 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 3 months, or has a positive drug toxicity screen
• 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 24 hours (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, we are not limiting the study to individuals with elevated levels of gliadin or casein antibodies as we intend to look at these levels as a predictor of response.

Adverse event data are presented for the treatment phase (Weeks 0 - 24) of the trial.

The occurrence of adverse events was assessed by asking participants about problems or health changes at all weekly phone calls and in-person study visits every four weeks throughout the 24-week treatment phase. Reported adverse events were categorized by organ system class.