The effects of pioglitazone adjuvant therapy on negative symptoms of patients with chronic schizophrenia: a double-blind and placebo-controlled trial.

Objective: The evident central role of inflammation, oxidative stress, and metabolic derangement in pathophysiology of negative symptoms of schizophrenia has opened new insights into probable pharmacological options for these symptoms. Pioglitazone is an antidiabetic agent with anti-inflammatory and antioxidant properties. In this study, we evaluated the efficacy of pioglitazone as an adjunct to risperidone for reduction of negative symptoms in schizophrenia.

Methods: In this randomized, double-blind, placebo-controlled trial, 40 patients with chronic schizophrenia and a minimum score of 20 on the negative subscale of Positive and Negative Syndrome Scale (PANSS) were randomly allocated to receive risperidone plus either pioglitazone (30 mg/day) or placebo for 8 weeks. Patients' symptoms and adverse events were rated at baseline and weeks 2, 4, 6, and 8. The difference between the two groups in decline of PANSS negative subscale scores was considered as the primary outcome of this study.

Results: At the study endpoint, patients in the pioglitazone group showed significantly more improvement in PANSS negative subscale scores (p < 0.001) as well as PANSS total scores (p = 0.01) compared with the placebo group.

Conclusion: These findings suggest the probable efficacy of pioglitazone as an augmentation therapy in reducing the negative symptoms of schizophrenia.