PEDIATRIC ORIGINAL ARTICLE Association between impulsivity, reward responsiveness and body mass index in children L van den Berg 1,2 , K Pieterse 1,3 , JA Malik 4 , M Luman 3 , K Willems van Dijk 2,5 , J Oosterlaan 3 and HA Delemarre-van de Waal 1 1 Department of Pediatrics, Leiden University Medical Center, Leiden, The Netherlands; 2 Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands; 3 Department of Clinical Neuropsychology, VU University Amsterdam, Amsterdam, The Netherlands; 4 Department of Developmental Psychology, VU University, Amsterdam, The Netherlands and 5 Department of General Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands Background: Childhood obesity is a major health problem. An association between children’s body mass index (BMI) and overeating has been established, but mechanisms leading to overeating are poorly understood. The personality characteristics impulsivity and reward responsiveness may be involved in the tendency to overeat. Impulsivity might relate to overeating through poor inhibition of food intake; reward responsiveness through the rewarding value of food. Objective: This study aimed to reveal the relationships between impulsivity, reward responsiveness, overeating and BMI in a sample of 346 Dutch children aged 6–13 years. The BMI distribution in the sample was representative of the BMI distribution in the Dutch pediatric population. Methods: Impulsivity and reward responsiveness were measured with the Dutch version of the parent-report Sensitivity to Punishment and Sensitivity to Reward Questionnaire for children. Overeating was assessed with the Dutch translation of the parent-report Children’s Eating Behaviour Questionnaire. Results: Overeating, impulsivity and reward responsiveness were significantly associated with childhood BMI. Mediation analysis revealed that impulsivity and reward responsiveness equally and significantly predicted BMI indirectly through overeating. Conclusions: The personality characteristics impulsivity and reward responsiveness predict childhood BMI indirectly through overeating. This suggests that these personality characteristics are risk factors for obesity. International Journal of Obesity (2011) 35, 1301–1307; doi:10.1038/ijo.2011.116; published online 21 June 2011 Keywords: childhood obesity; BMI; impulsivity; reward responsiveness; overeating Introduction Childhood obesity is a major health concern. It is associated with considerable health risks. For instance, glucose intolerance and insulin resistance are common in severely obese children. 1 In the Netherlands in 2002–2004, 13.5% of boys and 16.7% of girls aged 4–15 years were overweight, and 2.9% and 3.3%, respectively, were obese. 2 To address this public health problem, knowledge of the mechanisms underlying the development of overweight in children is required. Childhood body mass index (BMI; weight/length 2 ) was reported to be associated with overeating. 3 However, factors contributing to overeating in children are poorly understood. It has been proposed that the personality traits sensitivity to reward and impulsivity are involved in eating behavior (for example, refs 4–8). These personality characteristics are incorporated in Gray’s neuropsychological model of reinforcement sensitivity. 9 The model states that behavior is mediated by two independent brain systems, the behavioral inhibition system (BIS) and the behavioral approach system (BAS). The BIS is sensitive to aversive cues such as punish- ment and termination of reward. Activation of this system leads to avoidance behavior or inhibition of responses. The BAS, in contrast, is sensitive to signals of reward. Its activation leads to initiation of behavior, in order to pursuit the expected reward. The BAS consists of three factors: reward responsiveness (that is, the anticipation of and positive response to reward), impulsivity/fun seeking (that is, willingness to seek out and spontaneously approach potentially rewarding experiences) and drive (that is, Received 30 September 2010; revised 14 March 2011; accepted 7 May 2011; published online 21 June 2011 Correspondence: Dr L van den Berg, Department of Pediatrics and Department of Human Genetics, Leiden University Medical Center, PO Box 9600 (zone S-04-P), 2300 RC Leiden, The Netherlands. E-mail: L.vandenBerg@lumc.nl International Journal of Obesity (2011) 35, 1301–1307 & 2011 Macmillan Publishers Limited All rights reserved 0307-0565/11 www.nature.com/ijo