Psychological comorbidity is high in patients with obesity and is associated with a variety of medical and dietary problems as well as demographic, social and cognitive risk factors. Young overweight and obese women are at particular risk for developing sustained depressive mood, which is an important gateway symptom for major depressive disorder. Increased knowledge of behavioural risk factors has enabled patients with obesity to be classified on a psychological basis and this needs to be considered as part of a patient's clinical assessment and treatment strategy. Increased awareness of abnormal eating behaviour, together with profiling of personality traits, could improve treatment selection for obese women and improve the outcome of weight-loss programmes. Individualised antiobesity drug therapy may be required depending on the patient's psychological characteristics. International Journal of Obesity (2007) 31, S14-S18; doi:10.1038/sj.ijo.0803731Keywords: psychological correlates; comorbidity; psychogenic classification; depression; sibutramine As rates of obesity have risen, concern has principally focused on obesity-related comorbidities such as type 2 diabetes and cardiovascular disease. The relationship between obesity and psychological health has long been controversial and remains poorly understood. More recently, the emphasis has shifted to looking at the causal relationships between body weight and psychological distress and how this may affect treatment outcome.A number of potential risk factors for psychological suffering in obese individuals have been identified. These can be related to demographic factors, dietary behaviour, social/environment factors and cognitive factors (Table 1).Demographic risk factors include gender and age (with problems specifically occurring in young women), the degree of obesity, Hispanic ethnicity and lower socioeconomic class. In terms of eating/dietary behaviour, important psychological sequelae of obesity are dieting and restrained eating, binge eating and a high level of disinhibition with subjective feelings of constant hunger.Social and environmental risk factors include societal pressure to be thin, a long-standing history of stigmatisation in relation to obesity, discrimination, negative reactions from both family and peers, and poor interpersonal relationships. These can result in abnormal cognitive factors, with up to 74% of obese patients having body image dissatisfaction and distortion.1 Low self-concept and negative global attributions towards life are prominent. The individual's weight history is also relevant, with a history of weight cycling and childhood onset of obesity both being potential risk factors for later psychological suffering. The high prevalence of psychological comorbidities in obese patients was highlighted recently by Tuthill et al.