Cortisol suppression and circadian rhythm in endogenous depression: a preliminary report

We studied the relationships between dexamethasone challenge (DST), 36-hr sleep deprivation (SD), and body temperature patterns in ten male endogenous depressives. Seven of the ten depressives were pre-SD DST non-suppressors, and five of the ten patients improved following SD. All five SD responders were pre-SD DST non-suppressors. Pre- and post-SD 12-hr daytime body temperature patterns defined three subgroups of depressives. SD responders with DST non-suppression showed a normal diurnal temperature pattern on both pre- and post-sleep deprivation. SD non-responders with DST non-suppression showed a diurnal variation, but time of maximum temperature value was phase-advanced before SD and delayed after SD. SD non-responders with DST suppression had a blunted diurnal temperature pattern on both pre- and post-SD. We conclude that a normal pre-SD temperature pattern together with pre-SD DST non-suppression may predict clinical response to SD suggesting the possibility of physiologically distinct subgroups of endogenous depressives.