Patterns of co-morbidity of eating disorders and substance use in Swedish females.

BACKGROUND: Little is known about the association of eating disorder subtypes across multiple categories of substance use in population-based samples. We examined the association between eating disorders and substance use in a large population-based sample.
METHOD: Female participants (n=13 297) were from the Swedish Twin Registry [Lichtenstein et al., Twin Research and Human Genetics (2006) 9, 875-882]. Substance use was examined in four defined groups - (1) anorexia nervosa (AN); (2) bulimia nervosa (BN); (3) AN and BN (ANBN); and (4) binge eating disorder (BED) as well as a referent group without eating disorder (no ED). Secondary analyses examined differences between restricting AN (RAN) and binge and/or purge AN (ANBP).
RESULTS: In general, eating disorders were associated with greater substance use relative to the referent. The AN group had significantly increased odds for all illicit drugs. Significant differences emerged across the RAN and ANBP groups for alcohol abuse/dependence, diet pills, stimulants, and polysubstance use with greater use in the ANBP group. Across eating disorder groups, (1) the BN and ANBN groups were more likely to report alcohol abuse/dependence relative to the AN group, (2) the ANBN group was more likely to report diet pill use relative to the AN, BN and BED groups, and (3) the BN group was more likely to report diet pill use relative to the no ED, AN and BED groups.
CONCLUSIONS: Eating disorders are associated with a range of substance use behaviors. Improved understanding of how they mutually influence risk could enhance understanding of etiology and prevention.