Dexamethasone suppression test using saliva cortisol measurement in bulimia nervosa

The assessment of cortisol in saliva has been proven a valid and reliable reflection of the respective unbound hormone in blood. In the present study, a standard dexamethasone suppression test (DST) with measures of salivary cortisol levels was performed in bulimic women without depression (DSM-IV; N=48) and healthy controls (N=24) matched for age. Feedback sensitivity was assessed using the standard DST with pre- and post-measures of salivary cortisol. Subjects were divided into suppressors and nonsuppressors according to their post-DST levels. Bulimic suppressors and nonsuppressors were compared for their basal cortisol levels, body weight (body mass index, BMI), previous episodes of anorexia nervosa, and their results in psychometric tests. A total of 16 (33.3%) out of 48 women with bulimia nervosa (BN) failed to suppress in the DST. Basal salivary cortisol levels were elevated in bulimic nonsuppressors. Significant differences between suppressors and nonsuppressors were found for body weight and previous episodes of anorexia nervosa. The results are in accordance with recent findings. They support the hypothesized association between low body weight and DST nonsuppression. Using saliva cortisol in the standard DST could be advantageous for studying bulimic patients. Furthermore, the results show the importance of determining HPA reagibility when measuring cortisol in bulimic patients.