Psychological and psychophysiological correlates of binge eating

Binge Eating Disorder (BED) has been included in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV; American Psychiatric Association [APA], 1994), as a new diagnostic condition that requires further investigation. The main feature of BED is uncontrolled binge eating, which overlaps with the DSM-IV (APA, 1994) diagnostic criteria of Bulimia Nervosa (BN). In contrast to BN, BED commonly occurs in overweight people. It has been speculated that individuals with BED represents a subset of the obese population. Therefore, there is debate as to whether BED is a distinct diagnostic entity, is a less severe form of BN, or is a manifestation of disturbed eating that does not warrant psychiatric status. The aim of this research was to clarify whether BED characterises disturbed or disordered eating. A range of factors have been identified that may contribute to the development of disturbed or disordered eating. There is evidence to suggest that there is some overlap in the factors associated with the development of BN, BED and obesity. However, the behaviour of each of these groups indicates that the processes involved may be different. The continuity model of eating proposes that eating behaviour is distributed along a continuum, with normal eating occurring at one end, disordered eating at the other, with disturbed eating occurring at a point in between these. In terms of the continuity model, two propositions are raised with regard to BED. Proposition 1 speculates that the behaviour of individuals with BED represents disordered eating and, therefore, is more similar to BN. Proposition 2 states that BED represents disturbed eating and, therefore, individuals with BED are more similar to overweight individuals in terms of behaviour. Four groups were involved in this study. The first group all engaged in binge eating and compensatory purging behaviours. Most of this group currently had a diagnosis of BN although a small number currently did not meet the frequency of binge eating criterion and would be diagnosed with an Eating Disorder, Not Otherwise Specified (EDNOS). The second group met the diagnostic criteria for BED. The third group did not engage in binge eating or purging behaviours but were overweight (OW) with a Body Mass Index greater than 25. Finally, a normal weight group (NW) who did not display disturbed or disordered eating was included for control purposes. In Study 1, self-report and semi-structured interviews were administered to determine demographic characteristics, along with measures of eating and general symptomatology. BN and BED groups differed in demographic characteristics, whereas the BED and OW groups were more similar. In terms of symptomatology, the BN group reported the highest levels, with the BED group being more similar to the BN than OW group. In Study 2, 3, and 4, a five stage, personalised guided imagery methodology was utilised. Study 2 examined objective and subjective psychophysiological responses to binge eating or overeating, with comparisons being made to normal eating and non-eating neutral events. There was little evidence of variation between groups on objective measures of arousal across the binge episode. In contrast, for subjective measures, whereas the overall pattern of response was similar for all groups, the intensity of the response was greater for the BN and BED groups. For example, the BN and BED groups reported higher levels of tension and physical discomfort than the OW and NW groups.