Effect of Red Yeast Rice on Cognitive Functioning in Schizophrenia: Data from a Pilot Study

Background: Cognitive deficits (CDs) in schizophrenia affect poor outcome and real-world community functioning. Because redox imbalance has been implicated, among other factors, in the pathophysiology of CDs, antioxidant compounds may have a beneficial effect in their treatment. Red yeast rice (RYR), besides its lipid-lowering effect, exhibit antioxidant and anti-inflammatory. Methods: Thirty-five schizophrenia outpatients (age range, 18-60 years) on stable antipsychotic treatment and assessed by neuropsychological (Wisconsin Card Sorting Test [WCST], Verbal Fluency, and Stroop task) and psychodiagnostic instruments (Brief Psychiatric Rating Scale) received RYR at daily dosage of 200 mg/d (total monacolin K/capsule content, 11.88 mg) for 12 weeks. Results: Red yeast rice supplementation significantly improved WCST "perseverative errors" (P = 0.015), "total errors" (P = 0.017, P = 0.001), and phonemic fluency test (P = 0.008); a trend for improvement on other WCST variables ("nonperseverative errors," "perseverative responses," and "categories") was observed. Effect sizes, according to Cohen's suggestions, were small in all explored cognitive dimensions. There were no significant change in clinical symptoms and no subject-reported adverse effects. Conclusions: Despite several limitations (open design, lack of a control group, short period of observation, small sample size, mode of controlling patients' compliance, the lack of assessment of patients' functional improvement), results suggest that RYR supplementation may be a potentially promising strategy for addressing CDs in schizophrenia; further randomized, placebo-controlled studies are needed to better evaluate the potential role of RYR for the treatment of CDs in schizophrenia.