Introduction of old and new generations of antipsychotics leads to significant improvements in the positive symptoms of schizophrenia. However, negative symptoms remain refractory to conventional trials of antipsychotic therapy. Recently, there were several open clinical human trials with curcumin. Curcumin is a natural polyphenol, which has a variety of pharmacological activities, including antioxidative and neuroprotective effects. The studies showed that curcumin improved the negative symptoms of schizophrenia. The purpose of our study was to examine the efficacy of curcumin as an add-on agent to regular antipsychotic medications in patients with chronic schizophrenia.
Thirty-eight patients with chronic schizophrenia were enrolled in a 24-week, double-blind, randomized, placebo-controlled study. The subjects were treated with either 3000 mg/d curcumin or placebo combined with antipsychotics from January 2015 to February 2017. The outcome measures were the Positive and Negative Symptoms Scale (PANSS) and the Calgary Depression Scale for Schizophrenia.
Analysis of variance showed significant positive changes in both groups from baseline to the end of the study in all scales of measurement. There was a significant response to curcumin within 6 months in total PANSS (P = 0.02) and in the negative symptoms subscale (P = 0.04). There were no differences in the positive and general PANSS subscales, and the Calgary Depression Scale for Schizophrenia scores between the treatment and placebo groups. No patient complained of any adverse effect.
The promising results of curcumin as an add-on to antipsychotics in the treatment of negative symptoms may open a new and safe therapeutic option for the management of schizophrenia. However, these results should be replicated in further studies.
ClinicalTrials.gov Identifier: NCT 02298985