Original article Influence of resting energy expenditure on weight gain in adolescents taking second-generation antipsychotics q Cristina Cuerda a, * , Jessica Merchan-Naranjo b , Cristina Velasco a , Alberto Gutierrez b , Marta Leiva b , Maria J. de Castro b , Mara Parellada b , Marisa Giráldez b , Irene Bretón a , Miguel Camblor a , Pilar García-Peris a , Elena Dulín c , Inmaculada Sanz c , Manuel Desco d , Celso Arango b a Unidad de Nutrición, Hospital General Universitario Gregorio Marañón, Madrid, Spain b Unidad de Adolescentes, Departamento de Psiquiatría, Hospital General Universitario Gregorio Marañón, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Madrid, Spain c Biochemistry Department, Hospital General Universitario Gregorio Marañón, Madrid, Spain d Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM Madrid, Spain article info Article history: Received 12 November 2010 Accepted 16 March 2011 Keywords: Antipsychotics Resting energy expenditure Weight gain Metabolic side effects Adiponectin Adolescents summary Background & aims: : Weight gain is an undesirable side effect of second-generation antipsychotics (SGAs). We performed this study to examine the influence of SGAs on resting energy expenditure (REE) and the relationship of REE to weight gain in adolescent patients. Methods: Antipsychotic-naïve or quasi-naïve (<72 h of exposure to antipsychotics) adolescent patients taking olanzapine, quetiapine, or risperidone in monotherapy were followed up for one year. We per- formed a prospective study (baseline, 1, 3, 6, and 12 months after treatment) based on anthropometric measurements, bioelectrical impedance analysis, and indirect calorimetry (DeltatracÔ II MBM-200) to measure REE. We also analyzed metabolic and hormonal data and adiponectin concentrations. Results: Forty-six out of the 54 patients that started treatment attended at least 2 visits, and 16 completed 1 year of follow-up. Patients gained 10.8 Æ 6.2 kg (60% in the form of fat mass) and increased their waist circumference by 11.1 Æ 5.0 cm after 1 year of treatment. The REE/kg body mass ratio decreased (p ¼ 0.027), and the REE/percentage fat-free mass (FFM) ratio increased (p ¼ 0.007) following the fall in the percentage of FFM during treatment. Weight increase was significantly correlated with the REE/ percentage FFM ratio at all the visits (1e3e6e12 months) (r ¼ 0.69, p ¼ 0.004 at 12 months). Conclusions: SGAs seem to induce a hypometabolic state (reflected as decreased REE/kg body mass and increased REE/percentage FFM). This could explain, at least in part, the changes in weight and body composition observed in these patients. Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. 1. Introduction Second-generation antipsychotics (SGAs) have created a certain expectation among psychiatrists, and this may explain the wide- spread use of these drugs in the USA 1 and in Europe. 2e4 Although SGAs produce fewer extrapyramidal side effects 5 in terms of efficacy, recent reports have weakened many of the previous expectations with regard to their effect in dimensions other than distortion of reality (e.g. negative or cognitive symptoms). 6,7 Antipsychotic drugs induce weight gain and stimulate appetite. Since the introduction of SGAs, the incidence of obesity, diabetes mellitus, dyslipidemia and metabolic syndrome has increased in people taking these drugs. 8,9 The frequency of metabolic side effects varies in the adult population. They are most commonly observed with clozapine and olanzapine, to a moderate extent with q Parts of the manuscript have been previously presented at the International Congress on Schizophrenia Research, Colorado, USA, March 28-April 1, 2007; the meeting of the American Society for Parenteral and Enteral Nutrition, Dallas, USA, February 12e15, 2006; the meeting of the European Society for Parenteral and Enteral Nutrition, Istambul, Turkey, October 19e22, 2006; and the meeting of the American Society for Parenteral and Enteral Nutrition, Las Vegas, Nevada, USA, February 8e12, 2010. * Corresponding author. Unidad de Nutrición, Hospital General Universitario Gregorio Marañón, Doctor Esquerdo 46, 28007 Madrid, Spain. Tel.: þ34 915868541; fax: þ34 915868540. E-mail address: mcuerda.hgugm@salud.madrid.org (C. Cuerda). Contents lists available at ScienceDirect Clinical Nutrition journal homepage: http://www.elsevier.com/locate/clnu 0261-5614/$ e see front matter Ó 2011 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved. doi:10.1016/j.clnu.2011.03.007 Clinical Nutrition 30 (2011) 616e623