Effect of Early Intervention with Omega-3 on Insulin Resistance in Patients Initiated on Olanzapine with either Sodium Valproate or Lithium: A randomized, Double-blind, Placebo-Controlled Trial

OBJECTIVE: Metabolic side effects of the second generation (atypical) antipsychotics have been a forefront of attention since their availability. One common concern is the development of hyperglycemia and insulin resistance. The aim of this study was to evaluate the effect of early initiation of omega-3 fatty acids supplementation on glucose-insulin homeostasis in a group of psychiatric patients under treatment with olanzapine and sodium valproate or lithium combination. METHOD: In a double-blind design, eligible participants with schizophrenia, bipolar I, and schizoaffective disorders who were initiated on olanzapine combination with sodium valproate or lithium were randomly assigned to receive omega-3 or identical placebo capsules for 6 weeks. Fasting blood sugar (FBS), insulin and HbA(1c) were measured at the baseline and at the end of the 6(th) week. Homeostatic model assessment of insulin resistance (HOMA-IR), as a measure of insulin resistance, was also determined at the same times. RESULTS: At the end of the study, no significant difference was observed between the two arms in terms of FBS, fasting insulin, HbA(1c) and HOMA-IR. However, trends toward decreasing both fasting insulin levels (p=0.06) and HOMA-IR (p=0.07) were noted in the group receiving omega-3. No significant changes in the outcome variables were observed from the baseline to the final measurements in both groups. CONCLUSION: This study noted that adding omega-3 fatty acids at the commencement of olanzapine combination therapy with valproate or lithium could not favorably influence glucose-insulin homeostasis. However, trends toward a decrease in insulin levels (p=0.06) and HOMA-IR (p=0.07) observed in patients receiving omega-3 suggest a possible beneficial role of this supplement in this population and, therefore, warrant further evaluation.