Probiotics Show Promise in Easing Some Schizophrenia Symptoms

Adding probiotics to the diets of patients with schizophrenia may help treat yeast infections and bowel problems (common conditions in schizophrenia), and in some cases, reduce positive psychiatric symptoms, such as delusions, hallucinations, and hostility, according to a small pilot study at Johns Hopkins Medicine and Sheppard Pratt Health System.

Perhaps most notably, patients who saw the greatest improvements in psychiatric symptoms had no yeast infections to begin with. The researchers hypothesize that probiotics may have an easier time shifting the microbiome to a more balanced state when no fungal competitors are present.

The findings, published in the journal Brain, Behavior, and Immunity, add to the growing body of evidence showing a close link between the mind and the gut.

“The mental health field is in desperate need of new treatments for psychiatric disorders, yet there’s been very little progress toward this goal for too long a time. The tiny living organisms that make up the human microbiome and the overwhelming evidence for a gut-brain axis together represent a new frontier for schizophrenia research,” said Emily Severance, Ph.D., assistant professor of pediatrics and part of the Stanley Division of Developmental Neurovirology at the Johns Hopkins University School of Medicine.

“We need to rethink how we study brain disorders such as schizophrenia by looking at clues offered by a whole-body approach and identifying and understanding the basis for dysfunctions that are occurring outside the brain.”

In a previous study, the researchers investigated whether probiotics could treat general psychiatric symptoms and bowel function in people with schizophrenia. At the time, they observed bowel improvement but didn’t notice an impact on total psychiatric symptoms.

In addition, the group observed greater memory problems in people with schizophrenia who also had Candida yeast infections.

The new study involved 56 adult participants with an average age of 46. Nineteen participants were women, and 61 percent were white. At the start of the trial, each participant gave a blood sample and completed the Positive and Negative Syndrome Scale (PANSS) exam used for measuring a standard set of symptoms of schizophrenia.

Each patient was given one placebo pill per day with a meal for the next two weeks and were later split into groups so that neither the researchers nor the participants knew who would be given a real probiotic or the placebo for the next 14 weeks. Each probiotic pill contained over one billion colony-forming units of Lactobacillus rhamnosus and Bifidobacterium animalis.

PANSS scores were taken every two weeks, and the participants self-reported on their bowel movements weekly on a scale of zero to four. At the end of the study, the patients gave another blood sample.

Using the blood samples, the researchers measured antibody levels to yeast Saccharomyces cerevisiae, known as brewer’s yeast, and Candida albicans, known to cause yeast infections, before and after the probiotic treatment. Both types of yeast are elevated in people with schizophrenia.

The findings show that Candida antibody levels decreased by 43 percent over time in the 22 men taking probiotics but saw only a three percent decrease of antibodies in the 15 men receiving the placebo. Eighteen men responded to the treatment with reduced antibody levels; four men didn’t respond to the treatment.

For the next analysis, the researchers focused on the men who had evidence of a yeast infection due to elevated Candida antibodies. The five men in the placebo group with Candida had more difficulty with bowel movements over time, with an average bowel score of 0.74, compared to the 10 men without evidence of infection, who had an average score of 0.19.

These results reinforce their previous findings that Candida yeast can contribute to bowel difficulties in men with schizophrenia.

Next the researchers investigated whether PANSS psychiatric symptom scores varied between those males with schizophrenia if they had a Candida infection or not. The PANSS exams measure symptoms on three scales: the positive symptoms, such as delusions, hostility, grandiosity, and hallucinations; negative symptoms, like social withdrawal and poor socialization; and general psychological symptoms, such as guilt, anxiety, and depression.

Previous data from a larger study of schizophrenia showed that 165 men with Candida infections had higher levels of positive symptoms, such as delusions and hostility.

In patients treated with probiotics, PANSS scores on positive symptoms improved the most — from an average of 18 down to 14.6 on their PANSS score after 13 weeks — in those who didn’t have a Candida infection to begin with.

“The biggest change in psychiatric symptoms over time by probiotics in men without elevated Candida levels suggests that introduced bacteria via probiotics might shift the resident bacterial community dynamics more easily to a balanced state when fungal competitors such as Candida are not present,” said Severance. “Compared to the bacterial microbiome, relatively little is known about the fungal community in the gut and how it interacts with other classes of microbiota.”

“We hope that with additional studies, we can show that something as cost-effective and easy to access as probiotics would be a way to lessen some symptoms of schizophrenia,” says Severance.

Source: Johns Hopkins Medicine