Are Yeast Infections Linked to Mental Illness?

Candida albicans overgrowth was more prevalent in people with mental illness compared to those without psychiatric disorders in a “surprisingly” sex-specific manner, according to a new study.

“The levels of IgG antibodies directed against the Candida albicans were elevated in males with schizophrenia and bipolar disorder compared to controls,” said lead study author Emily Severance, PhD, assistant professor of pediatrics and member of the Stanley Division of Developmental Neurovirology at the Johns Hopkins University School of Medicine. “In females, there were no differences in antibody levels between these groups, but in women with mental illness who had high amounts of these antibodies, we found significant memory deficits compared to those without evidence of past infection.”
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The researchers investigated case-control differences in exposure to the opportunistic fungal pathogen, C. albicans, and examined associations with cognition, medication, lifestyle, and somatic conditions. They quantified C. albicans IgG antibodies in 2 cohorts totaling 947 individuals and evaluated odds ratios (OR) of exposure with psychiatric disorder using multivariate regressions.

The case-control cohort included 261 with schizophrenia, 270 with bipolar disorder, and 277 non-psychiatric controls; the second included 139 with first-episode schizophrenia, 78 of whom were antipsychotic-naïve.

The investigators found no differences in C. albicans exposures until diagnostic groups were stratified by sex. In males, C. albicans seropositivity conferred increased odds for a schizophrenia diagnosis (OR 2.04-9.53, p<0.0001). In females, C. albicans seropositivity conferred increased odds for lower cognitive scores on Repeatable Battery for the Assessment of Neuropsychological Status in schizophrenia (OR 1.12, p<0.004), with significant decreases on memory modules for both disorders (p<0.0007-0.03). C. albicans IgG levels were not impacted by antipsychotic medications. Gastrointestinal disturbances were associated with elevated C. albicans in males with schizophrenia and females with bipolar disorder (p<0.009-0.02). C. albicans exposure was associated with homelessness in bipolar males (p<0.0015).

“This research stems in part from anecdotal dialogues that we had with people with psychiatric disorders and their families, and repeatedly the issue of yeast infections came up,” Severance said. “Primary care providers should evaluate patients in the context that Candida yeast infections are both generally preventable and treatable. It would be great if nutritional guidelines could be written and implemented to minimize conditions conducive to the development of these infections, but compliance may likely vary depending on the numerous factors that affect people living with these disorders.”

Future research will examine the mechanisms by which Candida might become pathogenic to the brain, she said. “For example, is it the organism itself or a toxin produced by the yeast that can travel to the brain? Or is it the body’s own immune response to the yeast that ultimately directly impacts the brain?”

-Mike Bederka

Reference:

Severance EG, Gressitt KL, Stallings CR, et al. Candida albicans exposures, sex specificity and cognitive deficits in schizophrenia and bipolar disorder [Published online May 4 2016]. npj Schizophrenia. doi: 10.1038/npjschz.2016.18.