Rationale: Individuals with schizophrenia are at increased risk of developing metabolic syndrome (MetS) due to their lifestyle and antipsychotic treatment. Our previous study showed that patients with both schizophrenia and MetS present an increased expression and production of tumor necrosis factor-alpha (TNF-alpha). Omega-3 fatty acids have a documented role in suppressing TNF-alpha; therefore, we hypothesized that they may be of value in relieving inflammation and improving metabolic disturbance in patients with both schizophrenia and MetS.
Objectives: This study employed a randomized placebo-controlled trial to investigate the effects of omega-3 fatty acids on MetS in patients with schizophrenia.
Methods: We recruited 80 patients with both schizophrenia and MetS who received long-term olanzapine monotherapy. The patients were randomly assigned to the OMG-3 group (n = 40) or the placebo group (n = 40).
Results: Patients with both schizophrenia and MetS had significantly higher levels of TNF-alpha than the control subjects (Z = - 4.37, P < 0.01). There was a significant correlation between omega-3 fatty acid treatment and reduced triglyceride (TG) levels (Fgroup × time = 13.42; df = 1, 66; P < 0.01) when the patients completed this study. Along with metabolic improvement, omega-3 fatty acids decreased TNF-alpha levels after 12 weeks of treatment (Fgroup × time = 6.71; df = 1, 66; P = 0.012). We also found that the extent of TNF-alpha decrease was significantly correlated with that of TG decrease (r = 0.38, P = 0.001).
Conclusions: Our findings provide suggestive evidence that omega-3 fatty acids have beneficial effects on TG metabolism in patients with both schizophrenia and MetS that parallel decreased inflammation levels.
Keywords: Metabolic syndrome; Olanzapine; Omega-3 fatty acid; RCT; TNF-alpha.