Schizophrenia and the Mycobiome: A Pilot Study

I don’t often find articles of interest about organisms of the human biome other than bacteria, but yesterday, I came across one looking at the mycobiome in schizophrenia that is definitely worth writing about.  I’ve actually covered research by this research team in the past. Several  years ago, they looked at people with schizophrenia and found high levels of antibodies to S.cerevisiae, a yeast, which is a marker for intestinal inflammation.

In the research I just finished reading, the scientists set out to test whether or not probiotics would affect antibody levels to yeasts.[i]  In this 14 week long double-blind, placebo-controlled study, they also tracked the effects of the probiotics on bowel issues and the severity of psychiatric symptoms in the participating 58 patients.  The probiotic used was Bifiform Balance, which is made in Denmark, and is a combination of 10 billion units of Lactobacillus rhamnosus and 10 billion units of Bifidobacterium animalis.  (I am not sure why this particular probiotic was chosen as no explanation is given in the paper.) During the first two weeks, all patients were given a placebo.  Thus, the treatment group really only got the probiotic for a total of 12 weeks.

C.albicans (more familiarly known as Candida) levels were similar in the male patients, but not in the females.  Strangely, but coincidentally, the females who received the placebo had much higher levels of antibodies than those who got the probiotic.  Thus, there was no significant treatment effect of probiotics in the females.  The study progressed using only the male patients, and in the males, C.albicans IgG (antibody) levels were significantly reduced in those receiving the probiotics, but not in the placebo group.

They also found that the males who tested positive for C.albicans antibodies had significantly higher levels of bowel issues.  However, scores for bowel difficulties did not differ in between those who tested positive and negative for antibodies in the treatment group.

What was most striking:  while psychiatric score improvements had not yet reached “statistical significance” when the 14 week study ended, the researchers found distinct trends.  The males who tested positive for the yeast antibodies had elevated positive symptom scores each week compared to those who were negative for Candida exposure.  That is, Candida exposure equaled more severe symptomatology. More than that:  as the study progressed, improvements in symptoms in the probiotic group was seen approaching statistical significance…but much greater improvement in positive symptoms was noted in the men who’d tested negative who were receiving the probiotic.  That is, the men who did not have Candida antibodies had a “…more accelerated improvement of positive symptoms…” from the probiotic.

For those unfamiliar with schizophrenia, symptoms are classified as positive and negative.  Positive symptoms are those that involve losing touch with reality, like hallucinations and delusions.  Negative symptoms involve disruption to normal emotions and behaviors, like a flat affect (lack of facial expression), reduced feelings of pleasure and so forth.[ii]

The study suggests that exposure to Candida is associated with worse positive psychiatric symptoms – and this was confirmed in a larger cohort of 384 males with schizophrenia.

The good news is, after only 12 weeks of a not-particularly-potent probiotic, there were noticeable improvements in some symptoms of schizophrenia.

I particularly liked this sentence in the conclusion of the paper:  “…the development of new treatment options of serious psychiatric disorders has been staggeringly static.”  (Ya think?!) They go on to say, “A growing acceptance of a role for environmental factors contributing to psychiatric disease etiology has resulted in a currently promising new array of treatment modalities residing within the framework of the gut-brain axis…Future studies should be directed at translating these findings into practical methods for the diagnosis and treatment of schizophrenia and related disorders.”

Amen to that.


[i] Severance, EG., et. al. Probiotic normalization of Candida albicans in schizophrenia: a randomized, placebo-controlled, longitudinal pilot study.  Brain, Behavior and Immunity. 2017:62:41-45.


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