Childhood and adolescent obesity: Issues and viewpoints

Childhood obesity, which often persists into adulthood (Eddy et al., 2007; Must & Anderson, 2003), has become an increasingly prominent public health problem. While the psychological effects of obesity have been appreciated (Erermis et al., 2004), there is also increasing evidence that it increases the risk of medical illnesses such as diabetes mellitus, coronary heart disease and hypertension with substantial associated public health impact (Lau et al., 2007; Maloney, 2011). Over the past few decades, childhood obesity has progressively become a worldwide epidemic, with its prevalence having increased in most countries of the world (Wang & Lobstein, 2006). In the USA alone, the prevalence of obesity in children and adolescents during the years 2009 and 2010 was recently estimated to approach 17% (Ogden et al., 2012). These considerations were the impetus for the focus of this issue of the International Review of Psychiatry being childhood and adolescent obesity. As the prevalence of childhood obesity has increased, so have the depth and breadth of publications examining the issue. Despite advances in certain areas of relevant research, such as genetics, much less is known about other aspects of childhood obesity, such as pharmacological treatment options. There are still many fundamental issues to be addressed. For instance, although many children will eat high calorie foods, not every child will become overweight or obese. Childhood obesity can be viewed as a multifaceted problem that can benefi t from an interdisciplinary approach integrating basic and clinical sciences. Biological factors (such as genetics, epigenetics and intrauterine environment), as well as behavioural (such as learned eating behaviour) and social factors (such as socio-economic status) may all contribute to childhood obesity. Given the worldwide childhood obesity epidemic, psychiatrists and other mental health practitioners encounter childhood overweight and obesity quite often in their practices. The co-occurrence of obesity and psychiatric illness is common given the high prevalence of both psychiatric disorders (Merikangas et al., 2010) and obesity (Ogden et al., 2012) independently in youths. Moreover, obesity can present as a comorbidity of psychiatric disorders, just as psychiatric disorders can present as a comorbidity of obesity. In addition, obesity can be exacerbated or even caused by many of the psychotropic medications used to treat our paediatric patients (Maayan & Correll, 2011). This special issue targets psychiatrists and other health and mental health practitioners facing these challenges. The papers in this volume of the International Review of Psychiatry focus on issues practitioners encounter concerning the clinical management of childhood obesity. The goal is to critically review the available evidence regarding multifaceted topics ranging from the basic sciences (such as genetics) to clinical approaches (such as psychosocial treatments), while also presenting the narrative viewpoints of the authors. This volume begins with an exploration of the epidemiology of childhood obesity. Youfa Wang and colleagues from the Johns Hopkins Global Center on Childhood Obesity and the Johns Hopkins Bloomberg School of Public Health review the global epidemic of childhood obesity, which has increased over the past decade to become a global public health crisis. The association between childhood obesity and socioeconomic status (SES) is also reviewed. Notably, the groups with greater access to energy-dense foods (low SES in industrialized countries and the reverse in developing countries) have more of a chance to become obese. A major emphasis of this issue is on the basic aetiological mechanisms of childhood obesity. The developmental aetiology of childhood obesity, as well as specifi c genetic contributions, neuroimaging evidence of reward pathway involvement and the infl uence of diet and sensitive developmental periods in taste preference are explored. First, Susan Carnell and colleagues from Columbia University present views about the aetiology of childhood obesity, and present a biobehavioural susceptibility model as a mechanistic framework to understand variability in appetitive traits and individual weight in obese youths. Genetics also plays an important role in the aetiology of childhood obesity, as described by Joanne Cecil from the University of St Andrews in the UK. Cecil and colleagues describe the role of the allelic variants of certain specific genes to International Review of Psychiatry, June 2012; 24(3): 173–175