Effects of nutritional intervention on body weight and body composition of obese psychiatric patients taking olanzapine

Objective: Weight gain is an established side effect of atypical antipsychotics in patients with severe mental illness (SMI). Previous studies have shown positive effects of nutritional interventions in weight loss. The purpose of this study was to investigate the effects of a nutritional intervention on the body weight and body composition of patients with SMI taking olanzapine in Greece. Methods: Eighty-two patients with SMI treated with olanzapine (22 men, 60 women) and, 58 healthy controls (12 men, 46 women) were followed for 3 mo. All patients with SMI were obese, with an average body mass index of 33.12 +/- 0.74 kg/m(2) and body weight of 94.61 +/- 2.50 kg. A nutritional program was designed for each participant based on anthropometric characteristics, health profile, and dietary needs. Pre- and postintervention anthropometric and body composition measurements were performed. Results: Significant weight loss and fat loss were found in the healthy controls and patients with SMI from baseline to 3 mo (P < 0.05). However, the patients with SMI had a less significant decrease in waist circumference (P < 0.05) compared with healthy controls. The healthy male controls and male patients with SMI demonstrated greater decreases in body weight and waist circumference compared with female participants (P < 0.05). Conclusion: Patients with SMI appear to respond effectively to a nutritional program demonstrating significant decreases in body weight and body composition despite the use of olanzapine. Because gender differences may exist in weight loss, it is possible that gender should be taken into account for a more appropriate treatment of obesity in this population.