Investigation of factors associated to crossover from anorexia nervosa restricting type (ANR) and anorexia nervosa binge-purging type (ANBP) to bulimia nervosa and comparison of bulimia nervosa patients with or without previous ANR or ANBP

Objective: To characterize factors associated to diagnostic crossover from anorexia nervosa restricting type (ANR) and anorexia nervosa binge-purging type (ANBP) to bulimia nervosa (BN) and to compare BN individuals with initial ANR or ANBP to subjects with stable BN.

Method: Two hundred thirty-eight patients with current and lifetime diagnosis of AN or BN underwent diagnostic, psychopathological, and historical examinations by means of ad hoc clinical interviews and rating scales.

Results: One hundred twenty-three individuals had a stable BN. Seventy patients had a diagnosis of ANR and 45 of ANBP at the time of disease onset; 24 ANR patients and 23 ANBP subjects developed BN, whereas 46 ANR patients and 22 ANBP subjects did not crossover. Although the rate of diagnostic crossover was higher in the ANBP group than in the ANR one, the difference was not statistically significant. Longer illness duration, higher maximum past body mass index (BMI), higher novelty seeking, and lower self-directedness resulted significantly associated to crossover from ANR to BN, whereas higher maximum past BMI, higher desired body weight, higher novelty seeking, and lower harm avoidance were significantly associated to crossover from ANBP to BN. As compared to stable BN subjects, BN patients with initial ANR exhibited lower minimum past BMI, lower desired body weight, higher drive for thinness, ascetism, and social insecurity scores; BN patients with initial ANBP exhibited lower minimum past BMI and decreased enteroceptive awareness scores.

Conclusions: Different clinical and personality factors seem to be associated to crossover from ANR and ANBP to BN. Moreover, BN with initial ANR seems to differ clinically from stable BN. These findings may have therapeutic and prognostic implications.