Could a probiotic soothe PTSD? new study tests Gut-Brain link in veterans

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion criteria * History of at least one deployment in support of OEF/OIF * Current diagnosis of PTSD per the Clinician Administered PTSD Scale-5 (CAPS-5) * Current diagnosis of Functional Bowel Disorder by ROME IV * CRP level of 1.0 mg/L or above at baseline * Medical clearance to participate by study providers * Age between 18 and 60 * Ability to provide informed consent * Willingness to abstain from probiotic supplements (pills, tablets, oils, foods, etc.) other than the investigational product provided until all study procedures are completed * Willingness to provide blood and stool samples Exclusion criteria * Inability to adequately respond to questions regarding the informed consent procedure * Currently involved in the criminal justice system as a prisoner or ward of the state * Non-English speaking * Current (past month) alcohol or substance abuse or dependence * Lifetime history of bipolar disorder or psychosis or anxiety disorders (excluding PTSD). * Consistent (e.g., 5x/week or greater) probiotic supplementation within the last month, including probiotic food products such as yogurt, as determined by phone screen interview and Probiotic Food Check List * Receiving intravenous, intramuscular, or oral antibiotics within the last month * Presence of central venous catheters (CVCs) * Gastrointestinal (GI) barriers as identified by the 2-week run-in period as determined by the study team * Participation in conflicting interventional research protocol * Vital signs outside of acceptable range, i.e., blood pressure \>160/100, pulse \>100 * Use of any of the following drugs within the last 6 months: antifungals, antivirals or antiparasitics (intravenous, intramuscular, or oral); oral, intravenous, intramuscular, or inhaled corticosteroids; cytokines or cytokine inhibitors; methotrexate or immunosuppressive cytotoxic agents * Acute disease at the time of enrollment (defer sampling until the participant recovers). Acute disease is defined as the presence of a moderate or severe illness with or without fever (e.g., oral temperature \>100° F) * Any medical condition deemed exclusionary by the Principal Investigators * History of cancer * Unstable dietary history as determined by the PIs (e.g., major changes in diet during the previous month, where the subject has eliminated or significantly increased a major food group in the diet) * Positive test for human immunodeficiency virus (HIV), Hepatitis B virus, or Hepatitis C virus * Any confirmed or suspected condition/state of immunosuppression or immunodeficiency (primary or acquired) including HIV infection, or those receiving immunosuppressive drugs or treatment including antineoplastic therapy, post-transplantation immunosuppressive therapy, and/or radiation therapy * Major surgery of the GI tract, with the exception of cholecystectomy and appendectomy, in the past five years. Any major bowel resection at any time * Female who is pregnant or lactating * Treatment for or suspicion of ever having had toxic shock syndrome * History of moderate and/or severe traumatic brain injury