Background. Individuals with bulimia nervosa report significant symptom fluctuation, and some studies have suggested a premenstrual exacerbation of binge frequency. The purpose of this study is to explore the hormonal correlates of symptom fluctuation in bulimia nervosa.

Method. For five consecutive weeks (one full menstrual cycle), eight women with bulimia nervosa and eight non-eating-disordered control women collected morning saliva samples and recorded several mood characteristics; the bulimic women also recorded binge and purge episodes. Subsequently, salivary cortisol and androgen levels were determined by radioimmunoassay.

Results. Bulimic symptoms were exacerbated in both the mid-luteal and premenstrual phases, when compared with the follicular and ovulatory phases (F(3,21)=3·76, P=0·026; contrast analysis t(7)=3·47, P<0·01). Fluctuation in cortisol was closely correlated with fluctuation of bulimic symptoms, with elevated cortisol secretion following symptom exacerbation (r(24)=0·64, P=0·001).

Conclusions. Bulimic symptom fluctuation appears to be related to two hormonal phenomena – phase of the menstrual cycle and cortisol secretion – with menstrual-cycle phase influencing bulimic symptom severity, and bulimic symptom severity effecting increases in cortisol secretion. Improved understanding of the hormonal causes and consequences of symptom fluctuation may lead to improved psychological and pharmacological treatments for bulimia nervosa.