A hypothesis is presented for eating disorders, based on Darwinian theory, that contends that these syndromes together with the phenomenon of the pursuit of thinness are manifestations of female intra-sexual competition. It is suggested that eating disorders originate in the human female's psychological adaptation of concern about physical attractiveness which is an important component of female 'mate attraction' and 'mate retention' strategies. It is argued that present-day environment of Western countries presents a range of conditions which have led to the overactivation or the disruption of the archaic female sexual strategy of maximizing 'mate value'. The present hypothesis deals with the ultimate level of causation and is therefore compatible with a range of theories of proximate causation. Although the present hypothesis is not directly testable, it makes predictions that are testable and refutable. Finally it is suggested that the sexual competition hypothesis has more explanatory power than existing evolutionary theories of eating disorders.

The relationship between eating disorders and female intrasexual competition (ISC) was studied. More specifically, it was predicted that Female ISC for mates would be the strongest predictor of bulimia, and that, in contrast, Female ISC for status would be the strongest predictor of anorexia nervosa. A group of 202 undergraduate women, attending the University of Arizona, Tucson, USA, participated in this study. These respondents completed surveys that contained the following measures: the Female competition for mates scale, the Female competition for status scale, the General Competitiveness Scale, the Eating Disorders Inventory (EDI), and an additional measure specific to Anorexia. The internal consistencies of the measures were computed using Cronbach's alpha, and the measures were found to have adequate measurement reliability. Correlations were computed and a structural equation model was constructed for all the subscales within the measures. The resulting model demonstrated that ISC for mates was ultimately the driving factor that contributed to Female competition for status, General competitiveness, Perfectionism, Body dissatisfaction, Drive for thinness, and both Bulimia and Anorexia. Contrary to initial expectations, the results supported a mostly spurious causal relationship between Female competition for status and anorexia, with the only indirect causal effect being through the influence of perfectionism, which was uniquely on anorexia and not on bulimia. The role of perceived personal and Ideal partner mate value was also explored. Although they were strongly positively related to each other, these were shown to have nearly equal and opposite effects on body dissatisfaction.

A new hypothesis is presented within the framework of evolutionary psychology that attempts to explain the origins of obsessive-compulsive disorder. It is suggested that obsessions and compulsions originate from the overactivity of a mental module that the majority of humans possess and has the function of generating risk scenarios without voluntary intervention. It is hypothesised that obsessional phenomena function as an off-line risk avoidance process, designed to lead to risk avoidance behaviour at a future time, thus distinguishing it from anxiety and related phenomena as on-line emotional states, designed to lead to the avoidance of immediate and direct risks. Finally, the hypothesis makes a number of specific predictions that are testable and refutable. It is contended that the present hypothesis if supported by empirical evidence could serve as a basis for future research on this important disorder.

The sexual competition hypothesis (SCH) contends that intense female intrasexual competition (ISC) is the ultimate cause of eating disorders. The SCH explains the phenomenon of the pursuit of thinness as an adaptation to ISC in the modern environment. It argues that eating disorders are pathological phenomena that arise from the mismatch between the modern environment and the inherited female adaptations for ISC. The present study has two aims. The first is to examine the relationship between disordered eating behavior (DEB) and ISC in a sample of female undergraduates. The second is to establish whether there is any relationship between disordered eating behavior and life history (LH) strategy. Participants completed a battery of questionnaires examining eating-related attitudes and behaviors, ISC, and LH strategy. A group of 206 female undergraduates were recruited. A structural equation model was constructed to analyze the data. ISC for mates was significantly associated with DEB, as predicted by the SCH. DEB was found to be predicted by fast LH strategy, which was only partially mediated by the SCH. The results of this study are supportive of the SCH and justify research on a clinical sample.

A survey was carried out to investigate general practitioners' attitude towards drug addicts and addiction. A questionnaire was sent to all GPs in the Norwich Health District and obtained an 87% response rate. A range of negative and positive attitudes was identified. The implications of these findings are discussed with particular reference to current government policy of encouraging GPs to extend their role in treating drug addiction.