RESUMEN
PURPOSE/BACKGROUND: It is well documented that one of the pathophysiological mechanisms of negative symptoms in patients with schizophrenia is hypofunction of N-methyl-d-aspartate receptors. This double-blind, placebo-controlled clinical trial was designed to assess the efficacy and safety of nanocurcumin as an adjuvant agent on psychotic symptoms, especially negative symptoms, in patients with chronic schizophrenia. METHODS/PROCEDURES: Fifty-six inpatients with stable chronic schizophrenia and predominant negative symptoms were randomized in a 1:1 ratio to nanocurcumin soft gel capsule (160 mg/d) and control groups, along with their antipsychotic regimen for 16 weeks. The efficacy of treatment was assessed by Positive and Negative Syndrome Scale, Calgary Depression Scale for Schizophrenia, Clinical Global Impressions-Severity, and Clinical Global Impressions-Improvement scales. Extrapyramidal symptoms were evaluated by Simpson-Angus Scale and Barnes Akathisia Rating Scale. Patients were assessed at baseline and weeks 4, 8, 12, and 16 after the medication started. FINDINGS/RESULTS: No significant differences were observed in demographic or clinical variables between both groups at baseline. The nanocurcumin group showed significantly greater improvement on the negative subscale (P = 0.05), the general psychopathology subscale (P < 0.001), the positive subscale (P = 0.004), total Positive and Negative Syndrome Scale (P < 0.001), Clinical Global Impressions-Severity (P < 0.001), and Clinical Global Impressions-Improvement scores (P < 0.001) in comparison with the control group at the endpoint. Extrapyramidal symptom rating scales and Calgary Depression Scale for Schizophrenia and frequency of other adverse effects were comparable between 2 groups. IMPLICATIONS/CONCLUSIONS: The present study indicates nanocurcumin as a safe and potential adjunctive treatment strategy for treatment of primary negative symptoms of schizophrenia.