Editorial [Hot Topic: Food and Addiction: Implications and Relevance to Eating Disorders and Obesity (Guest Editor: Nicole M. Avena)]

For many years researchers have noted the overlaps that exist in the brain mechanisms that promote ingestion of food and drug abuse [1, 2]. As just one example, the mesolimbic dopamine system has been implicated as being perturbed in both cases of drug dependence, as well as cases of caloric over and under consumption. Despite these known overlaps in brain mechanisms, historically, these two behaviors, feeding and drug dependence, have been studied independently. However, more recently, the idea that certain foods may have properties of addiction [3, 4] has been reinforced by empirical studies, and researchers have begun to study these behaviors simultaneously to understand whether “food addiction” might have a role in the present-day obesity crisis, as well as in certain eating disorders. The aim of this special issue is to summarize the current literature on concepts related to the intersects between food and addiction. Over the past few years a significant amount of work has been devoted to the study of “food addiction.” Preclinical studies have shown that overeating palatable foods can lead to addiction-like behaviors [3, 5]. Likewise, preclinical studies show that during some instances of aberrant eating there are concomitant changes in neurochemistry and gene expression in reward-related brain areas that are similar to the changes that can occur in response to a drug of abuse [6]. Clinical studies using patient self-report and neuroimaging support these findings, and suggest that individuals can meet criteria that suggest dependence on palatable foods [7, 8]. This raises important questions regarding the addictive nature of highly-palatable foods that are abundant in the modern food environment [9, 10]. The idea of “food addiction” has been extended and applied conceptually to disordered eating behavior. The obesity epidemic has led to many novel suggestions regarding its etiology, one of which is that some people may develop an unhealthy dependence on calorically-dense, palatable foods. Indeed, overweight individuals show altered reward responsivity and changes in the brain that are like those seen in individuals addicted to drugs, as revealed by fMRI and PET [11]. Obesity can arise when there is excessive motivation to eat and low impulse control, a situation that has been termed reinforcement pathology [12]. Theories of hypo-responsivity and hyper-responsivity to food in reward-related brain regions have been described. Further, newer data account for the possible effects of repeated overeating on brain responsivity to food and factors leading to vulnerability toward overeating [13]. Aside from obesity, the overlaps that exist between food intake and addiction have relevance to the study of eating disorders, such as anorexia nervosa and binge eating disorder. It is interesting that both over- and under-eating can perturb brain reward systems in a way that can promote the intake of drugs of abuse [14]. Anorexia nervosa, which is characterized by severe undernutrition, may result in some features of addiction. For example, patients narrow their behavioral repertoire of weight loss, restricting food intake, and excessive exercise such that these behaviors interfere with other activities in much the same way that substance abuse does [15]. Binge eating disorder has stood out as having particular relevance to “food addiction.” Binge eating, which is seen in obesity, as well as in some eating disorders, is characterized by periodic overeating. Such intermittent food consumption has been suggested to promote behaviors that are associated with dysregulation in rewardfunctioning [16]. Further, binge eating disorder shares many characteristics with addictive behaviors (e.g., diminished control and continued use despite negative consequences) [17]. While understanding the contributions that maladaptive food intake, as it relates to addiction, makes toward informing our understanding of the pathology of obesity and eating disorders, it is important to underscore that there are unique physiological and cognitive factors that contribute to each of these disorders. Nonetheless, the articles in this special issue highlight the recent research on the intersects of food reward and drug reward, and the information described posits important future considerations for treatment, policy and nutritional guidance.....