Anorexia nervosa (AN) is a complex psychiatric disorder characterized by severe restriction of food intake and aberrant behaviours. The endogenous stress response system, including the hypothalamus-pituitary-adrenal (HPA) axis, may have a role in the pathophysiology of AN.

It has been shown that specific clinical traits of AN, such as binge-purging behaviours, may be associated with higher psychopathology and poorer outcomes. Therefore, the HPA axis functioning could differ between patients with restrictive AN (ANR) and those with binge-purging AN (ANBP).

In order to evaluate whether HPA axis functioning differs between the two subtypes of AN, we assessed the cortisol awakening response (CAR) of symptomatic ANR and ANBP patients.

Our sample included 17 ANBP and 18 ANR patients, and 42 healthy women. All of them filled in the Eating Disorder Inventory-2 (EDI-2). For CAR assessment, participants collected saliva samples at home. Saliva cortisol concentrations were measured by an enzyme immunoassay method.

ANR and ANBP patients exhibited a CAR significantly higher than healthy women. Furthermore, the CAR of ANBP women was higher than that of ANR women and positively correlated with the bulimia subitem score of the EDI-2.

Present findings show, for the first time, differences in the CAR between ANBP and ANR subtypes supporting the idea that binge-purging behaviours may have a specific connection with HPA axis.

The authors have not supplied their declaration of competing interest.