Related Experiment Video
Updated: Aug 25, 2026

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
Published on: April 7, 2020
The circadian rhythm of plasma thyrotropin in depression and recovery
E Souetre1, E Salvati, D Pringuey
1Clinique de psychiatrie et de psychologie médicale, Hôpital Pasteur, Nice, France.
Abstract:
The 24-hr patterns of plasma thyrotropin have been observed in 12 endogenous depressed patients in both depressed and recovered states and in 13 normal subjects. A clear circadian rhythm was detected in controls with high values at night. In depression, the circadian rhythm was altered with amplitude reduction and blunted nocturnal secretion, abnormalities particularly relevant in bipolar patients. This flattened profile could be linked to the blunted response of TSH to TRH administration reported in depressed patients. Normal nyctohemeral patterns have been restored after recovery. These chronobiological abnormalities as well as their normalization under antidepressant drugs seem to be similar to those reported for various parameters (e.g. temperature, cortisol, etc) in depression which could support the chronobiological hypothesis for affective disorders.
Related Concept Videos
Circadian Rhythms and Gene Regulation
Depression: Overview
Management of Insomnia
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Depressive Disorders: MDD and Dysthymia
Graves Disease II: Pathophysiology

