SEASONAL-VARIATION IN-CORE TEMPERATURE REGULATION DURING SLEEP IN PATIENTS WITH WINTER SEASONAL AFFECTIVE-DISORDER

Nocturnal core temperature during sleep is elevated during depression compared with remission in nonseasonally depressed patients. Similarly , nocturnal core temperature is higher during winter depression compar ed with remission induced by light treatment in seasonal affective dis order (SAD) patients. We investigated whether nocturnal core temperatu re in SAD patients naturally becomes lower in summer (during remission ) compared with winter (during depression). Twenty-four-hour core temp erature profiles were obtained in winter and summer in 22 SAD patients and 22 controls, The nocturnal core temperature minima were fewer in summer compared with winter in SAD patients (p < .005), but not contro ls (p > .4). The seasonal charges in nocturnal core temperatures in SA D patients may reflect a unique physiological responsiveness of SAD pa tients to the change of seasons, and may be intimately related to the seasonal disturbances of mood and energy that are characteristic of SA D. (C) 1997 Society of Biological Psychiatry.