The dexamethasone suppression test (DST) was investigated in 45 female anorectic out-patients (cross sectional study) nine of whom were followed serially as in-patients (longitudinal study). DST non-suppression was strongly associated with negative energy balance (low body weight and low Ponderal Index) but there was no significant association with the presence of affective or neurotic disturbance in these patients. These findings cast doubt on the value of the DST in the management of depressive illness.