Caught in the Bulimic Trap? Socioeconomic Status, State Dependence, and Unobserved Heterogeneity

Eating disorders are an important and growing health concern, and bulimia nervosa (BN) accounts for the largest fraction of eating disorders. Health consequences of BN are substantial and especially serious given the increasingly compulsive nature of the disorder. However, remarkably little is known about the mechanisms underlying the persistent nature of BN and the socioeconomic groups that are most likely to be at risk. Using a unique panel data set on young women and instrumental variable techniques, we document that unobserved heterogeneity plays a role in the persistence of BN, but strikingly up to two thirds is due to true state dependence. Our results, together with support from the medical literature, provide strong evidence that bulimia should be considered an addiction. We also find that African Americans are more likely to exhibit and persist in bulimic behavior than Whites; as are girls from low income families compared to middle and high income families. These results stand in stark contrast to the popular conceptions of who is most likely to experience BN, and we argue that this is due to differences in the diagnosis across racial and income classes. Our findings have important implications for public policy since they i) provide direction to policy makers regarding which adolescent females are most at risk for BN, and ii) suggest that the timing of the policy is crucial: preventive educational programs should be coupled with more intense (rehabilitation) treatment at the early stages of bingeing and purging behaviors. Our results are robust to different model specications and identifying assumptions.