Taking probiotic supplements was significantly linked to fewer rehospitalizations in manic patients recently discharged from the hospital, according to a new study published in Bipolar Disorder. Furthermore, the effects of probiotics were heightened in subjects with higher levels of systemic inflammation.
“Previous studies have identified correlations between immunological abnormalities and mania, and this may contribute to the acute mood state,” said lead author Faith Dickerson, PhD, MPH, head of the Stanley Research Program, Sheppard Pratt Health System, Baltimore, MD. “With increasing evidence about the potential benefits of probiotics to regulate mood through the gut-brain axis, we saw an opportunity to further explore the use of probiotics as there have been no published trials with mania.”
Probiotic microorganisms have been shown to exert both anti-inflammatory and immune regulatory effects on gastrointestinal inflammation, thus changing mood via the gut-brain axis.
“Based on these considerations,” the authors wrote, “we undertook a placebo-controlled double-blind study to determine whether the administration of probiotic microorganisms as adjunctive treatment added to standard psychiatric medications could prevent psychiatric rehospitalizations in individuals who had recently been discharged following hospitalization for mania.”
The researchers enlisted participants with bipolar I disorder aged between 18 and 65 years from inpatient and day-hospital programs for manic symptoms. Following discharge from the hospital, 66 subjects were randomized to receive either a daily tablet containing Lactobacillus GG and Bifidobacterium lactis strain Bb12 or a placebo. Both patient groups continued with their prescribed psychiatric and other medications.
The treatment phase ran for 24 weeks, with in-person psychiatric symptom evaluations every 4 weeks starting on week 4 of the study. The researchers also took blood samples at baseline to determine participants’ inflammation scores.
The primary outcome for this study was the time it took for manic patients to be rehospitalized. The researchers measured probiotic effect on rehospitalization risk using Cox regression analysis. They controlled for age, race, and gender.
The team found that probiotic supplementation was associated with an approximately 2.5- to 3-fold lower hazard of rehospitalization. During the 24-week study period, 51% of participants receiving placebo were rehospitalized compared with 24% in the probiotic group. Furthermore, probiotic supplementation led to fewer days of rehospitalization in the experimental group (mean 2.8 days) than those in the control group (mean 8.3 days, P=0.017).
Beneficial effects of probiotics were greatest in patients with higher levels of systemic inflammation at baseline, with these patients experiencing a 90% risk reduction of rehospitalization.
Notably, the researchers did not observe a probiotic effect on the symptom severity of mania. They suggested that this lack of effect could be due to the study’s widely spaced evaluations of symptoms that did not catch severe symptom episodes resulting in hospitalization.
“A life chart mood rating system, in which symptoms are rated more frequently, would better determine changes in symptoms associated with the probiotic treatment,” the researchers recommended.
One potential limitation of this study was that participants were prescribed different drug regimens by their providers, with no standardization in place. But overall, patients were taking similar drugs and had similar symptom severity scores at baseline.
“The probiotic compound was well tolerated and had low levels of side effects,” the researchers concluded. “The adjunctive use of probiotics might represent a major addition to the therapeutic armamentarium for the management of mania and other mood disorders.”