The psychobiology of comfort eating: implications for neuropharmacological interventions E. Leigh Gibson Comfort eating, that is eating induced by negative affect, has been a core theme of explanations for overeating and obesity. Psychobiological explanations and processes underlying comfort eating are examined, as well as its prevalence in clinical and nonclinical populations, to consider who may be susceptible, whether certain foods are comforting, and what the implications for treatment may be. Comfort eating may occur in a substantial minority, particularly in women and the obese. Human and animal theories and models of emotional or stress-induced eating show some convergence, and may incorporate genetic predispositions such as impulsivity and reward sensitivity, associated with dopamine dysregulation underlying incentive salience. Comfort eaters show vulnerability to depression, emotional dysregulation and a need to escape negative affect and rumination. During negative affect, they preferentially consume sweet, fatty, energy-dense food, which may confer protection against stress, evidenced by suppression of the hypothalamic–pituitary–adrenal axis response, although activation of the hypothalamic– pituitary–adrenal axis may itself drive appetite for these palatable foods, and the risk of weight gain is increased. Benefits to mood may be transient, but perhaps sufficient to encourage repeated attempts to prolong mood improvement or distract from negative rumination. Cognitive behavioural treatments may be useful, but reliable drug therapy awaits further pharmacogenomic developments. Behavioural Pharmacology 23:442–460  c 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins. Behavioural Pharmacology 2012, 23:442–460 Keywords: depression, dopamine D 2 receptors, emotional eating, glucocorticoid hormones, hypothalamic–pituitary–adrenal axis, mood, obesity, reward sensitivity, stress Department of Psychology, Whitelands College, University of Roehampton, London, UK Correspondence to Edward Leigh Gibson, BSc, PhD, Department of Psychology, Whitelands College, University of Roehampton, Holybourne Avenue, London SW15 4JD, UK E-mail: l.gibson@roehampton.ac.uk Received 15 May 2012 Accepted as revised 3 July 2012 Introduction This review considers the nature of comfort eating, and describes psychobiological explanations for it, in addition to discussing evidence for who might be susceptible and why, and what sustains comfort eating in those individuals. Although it is recognized that comfort eating may overlap with binge eating, this review is not specifically concerned with binge eating, which requires clear evidence of excessive and frequent intake; rather, comfort eating is considered a phenomenon that may be common in nonclinical populations, and may not necessarily involve episodes of excessive consumption. The relevance of comfort eating to public health is gauged by estimating its prevalence, particularly in nonclinical populations, from data available in the literature. Major theories are discussed that set comfort eating in the context of normal and abnormal eating behaviour and help to understand both how it may arise, including its relation to personality characteristics, as well as the implications for therapy. A key aspect of theories of comfort eating is understanding whether certain foods or food groups may be chosen by comfort eaters and why: theories are examined that attempt to explain why negative affect and stress may elicit eating in individuals with particular traits. The review also addresses whether comfort eating may be harmful to health, such as by increasing the risk of developing obesity or other disordered eating, or by damaging the cardio- vascular system through unhealthy food choices, or, by contrast, whether comfort eating might actually provide some benefits to health and well-being. Evidence for a role for particular neurotransmitter and neurohormonal systems is considered and thus whether neuropharmacological interventions may be feasible or even advisable. Defining ‘comfort eating’ In the academic literature, the normal understanding of comfort eating is eating to relieve negative emotions or affect (typically depression, anxiety or anger), which is synonymous with ‘emotional eating’ (at least where the definition is restricted to negative emotions), the latter being the more commonly used term in such literature (Ganley, 1989). Another term with similar meaning is ‘stress eating’, that is eating induced by stress; indeed, consideration of ‘who eats more when stressed and why’ is at the heart of understanding comfort eating. Even so, this implies that individuals who eat more when stressed do so because of some relief that eating provides, and clearly this needs to be evidenced. This review will focus on these issues, and the evidence for psychobiological mechanisms. An implicit assumption of stress-induced eating is that the stress results in the sort of negative affect that can elicit eating, and thus is not severe enough to suppress appetite. Whereas one can operationally define ‘comfort 442 Review article 0955-8810  c 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins DOI: 10.1097/FBP.0b013e328357bd4e Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.