Peak amplitude and frequency of urinary free cortisol excretion in patients with a history of major depressive disorder.

Seven male recovered depressive patients who were dexamethasone suppression test (DST) nonsuppressors while ill and eight male controls submitted an average of thirty-six 24-hr urine specimens for analysis during a 12-mo collection period. Recovered depressive patients had a significantly greater mean peak amplitude (mean distance from fitted regression line to the highest point on the peak) when compared to controls. Peak frequency (number of peaks per year) for recovered depressive patients for peaks greater than 30 micrograms/g-cr was three times that found in the control population. The number of collections by each patient did not account for these differences. Only one of seven recovered depressives had a circasemiannual rhythm of cortisol excretion while none demonstrated a seasonal rhythm. These findings suggest that patients with a history of depression and DST nonsuppression have greater variability in cortisol excretion than a control population while in the compensated state.