The effect of zonisamide on antipsychotic-associated weight gain in patients with schizophrenia: A randomized, double-blind, placebo-controlled clinical trial

Background: Many patients with schizophrenia suffer from metabolic symptoms and weight gain in which predispose them to obesity, diabetes, and cardiovascular problems. This trial examines the efficacy and safety of zonisamide on weight and body mass index in patients with schizophrenia being administered with atypical antipsychotics. Method: In this 10-week, double blind randomized placebo controlled clinical trial, forty one patients with schizophrenia diagnosed according to DSM-IV-TR criteria who were taking a stable dose of atypical antipsychotic are allocated into one of the two groups of zonisamide or placebo group. Weight, body mass index, waist circumference, and adverse effects were assessed. Results: The two groups were not statistically different regarding baseline characteristics on age, gender, education, diagnosis, weight, body mass index, daily cigarette smoking, and the duration of illness. After 10 weeks, the patients in the placebo group had significantly gained weight, while the patients in the zonisamide group lost weight (mean = 1.9, SD = 2.2 versus mean = -1.1 kg, SD = 1.4). The changes of body mass index in the two groups were significantly different. Body mass index decreased in the zonisamide group (mean = -0.3, SD = 0.4) while it increased in the placebo group (mean = 2.2, SD = 6.9). There was a significance difference between the two groups regarding waist circumference at the end of trial (P < 0.0001), too. The waist increased in the placebo group while it decreased in the zonisamide group (mean = 1.1, SD = 1.7 versus mean = -0.7, SD = 1.2, respectively), as well. The frequencies of adverse effects were not significantly different between the two groups and zonisamide was tolerated well. Conclusion: Zonisamide as an adjuvant treatment is tolerated well and markedly affect on the weight loss of patients with schizophrenia being treated with atypical antipsychotics. (C) 2013 Elsevier B. V. All rights reserved.