Lifestyle Intervention and Metformin for Treatment of Antipsychotic-Induced Weight Gain

<p>Weight gain, a common adverse effect of antipsychotic medications, is associated with medical comorbidities in psychiatric patients. </p>
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<p>The objective of the trial was to test the efficacy of lifestyle intervention and metformin alone and in combination for antipsychotic-induced weight gain and abnormalities in insulin sensitivity. </p>
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<p>The trial was designed as a randomized controlled trial (October 2004-December 2006) involving 128 adult patients with schizophrenia in the Mental Health Institute of the Second Xiangya Hospital, Central South University, China. Participants who gained more than 10% of their pre-drug weight were assigned to 1 of 4 treatment groups. </p>
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<p>Patients continued their antipsychotic medication and were randomly assigned to 12 weeks of placebo, 750 mg/d of metformin alone, 750 mg/d of metformin and lifestyle intervention, or lifestyle intervention only. </p>
<p>Main Outcome Measures Body mass index, waist circumference, insulin levels, and insulin resistance index. </p>
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<p>All 128 first-episode schizophrenia patients maintained relatively stable psychiatric improvement. The lifestyle-plus-metformin group had mean decreases in body mass index (BMI) of 1.8 (95% confidence interval [CI], 1.3-2.3), insulin resistance index of 3.6 (95% CI, 2.7-4.5), and waist circumference of 2.0 cm (95% CI, 1.5-2.4 cm). The metformin-alone group had mean decreases in BMI of 1.2 (95% CI, 0.9-1.5), insulin resistance index of 3.5 (95% CI, 2.7-4.4), and waist circumference of 1.3 cm (95% CI, 1.1-1.5 cm). The lifestyle-plus-placebo group had mean decreases in BMI of 0.5 (95% CI, 0.3-0.8) and insulin resistance index of 1.0 (95% CI, 0.5-1.5). However, the placebo group had mean increases in BMI of 1.2 (95% CI, 0.9-1.5), insulin resistance index of 0.4 (95% CI, 0.1-0.7), and waist circumference of 2.2 cm (95% CI, 1.7-2.8 cm). The lifestyle-plus-metformin treatment was significantly superior to metformin alone and to lifestyle plus placebo for weight, BMI, and waist circumference reduction. </p>
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<p>Lifestyle intervention and metformin alone and in combination demonstrated efficacy for antipsychotic-induced weight gain. Lifestyle intervention plus metformin showed the best effect on weight loss. Metformin alone was more effective in weight loss and improving insulin sensitivity than lifestyle intervention alone.</p>
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<p>SOURCE: JAMA. 2008;299(2):185-193. </p>