Exposure to Candida albicans significantly increased the odds of a schizophrenia diagnosis in men, according to case-control data from two cohorts of 947 adults.
“Fungal pathogens have not been extensively evaluated in studies of psychiatric disorders,” wrote Dr. Emily G. Severance of Johns Hopkins University in Baltimore, and her colleagues, in njp (Nature Partner Journals) Schizophrenia.
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The researchers compared C. albicans IgG levels of individuals with schizophrenia and bipolar disorder with controls and found no diagnostic differences. However, stratification by sex showed a significantly increased risk of schizophrenia in men with elevated C. albicans IgG levels, with a ninefold increase in risk at the highest of three levels of seropositivity (odds ratio, 9.53). Elevated C. albicans levels in males with bipolar disorder were attributed to a history of homelessness.
C. albicans antibodies in women were not significantly different between groups. However, C. albicans was significantly associated with cognitive impairment in women with schizophrenia vs. control women (OR, 1.12), but no such difference was noted in men.
High levels of C. albicans antibodies were associated with comorbid gastrointestinal, genitourinary, and neoplastic conditions among individuals with psychiatric disorders overall.
“It may be premature to list this pathogen as a risk factor for disease causation, but its status as a comorbidity requires clinical attention,” the researchers wrote. “In the long term, more research is required to understand the mechanisms that trigger pathogenicity of fungal commensals and how this might impact brain function in psychiatric disorders.”
The findings were published in npj Schizophrenia. Read the full study here (npj Schizophrenia 2016 May 4. doi: 10.1038/npjschz.2016.18).