THE EPIDEMIOLOGY AND CLASSIFICATION OF BULIMIA-NERVOSA

Background. We sought to determine whether there was empirical support for the diagnostic thresholds of DSM-IV bulimia nervosa (BN) and whet her an empirically derived typology resembled the diagnostic categorie s of DSM-IV. Methods. Detailed information about bulimic behaviours we re assessed via personal interview in a population-based sample of 189 7 Caucasian female twins. We assessed the lifetime prevalence of the c omponent bulimic behaviours and DSM-IV and DSM-III-R BN. Latent class analysis of nine separate bulimic symptoms was used to develop an empi rical typology of bulimic behaviour. Results. Although the lifetime pr evalences of bingeing (23.6%) and vomiting (4.8%) were relatively comm on, DSM-IV BN was distinctly uncommon (0.5%). The criterion that speci fied the frequency and duration of bingeing and vomiting was an import ant limiting condition. Analysis of alternative thresholds found littl e support for the DSM-IV thresholds requiring an average of twice per week for 3 months. Latent class analysis yielded an interpretable four class solution that had little overlap with the DSM-IV typology. Conc lusions. As in other studies of unselected samples of women, the lifet ime presence of bulimic behaviours are relatively high. Our results su ggest that the DSM-IV approach to categorizing bulimic behaviour inade quately captures the spectrum of lifetime bulimic behaviours in the ge neral population.