Circannual rhythm and peak frequency of corticosteroid excretion: relationship to affective disorder

A circannual rhythm of corticosteroid excretion has been identified in healthy subjects but is lost in patients who have recovered from a depression associated with dexamethasone nonsuppression. The loss of circannual variation as well as the persistent elevation and increased peak frequency of cortisol excretion could be instrumental in the development of depressive symptoms. A model for this phenomenon can be found in the entity known as intermittent Cushing's disease. That hypercortisolemia could be etiologically related to depression is supported by the case reported here in which a rise in UFC preceded the emergence of psychiatric symptomatology on two occasions. Further investigation into this possibility is clearly warranted.