The 24-hour patterns of body temperature and plasma thyrotropin (TSH)
were measured in eight bipolar patients in both depressed and recovered
(after 3 weeks of treatment) states and in eight normal control subjects.
Clear circadian patterns were detected for both temperature and TSH.
Nocturnal body temperature was increased and the nocturnal surge of TSH was
blunted during depression; these abnormalities were corrected after
recovery. The inverse relationship between changes in body temperature and
TSH levels at night suggests that changes in thermoregulation may be
responsible for the neuroendocrine disturbance and may play a role in the
pathophysiology of depression.