59. Clock genes at the heart of depression24 October 2010 at 02:25 | Posted in Circadian rhythm | 8 Comments
Tags: Body clock, Circadian rhythm, Depression, Diagnosis, Genetic mutation, Treatment
Which came first: the chicken or the egg? The circadian rhythm dysregulation or the depression?
Traditionally, it has been claimed (assumed) that depression causes sleep problems including sleeping too early (the thinking in the 1980s) or too late (more recently). We who have circadian rhythm disorders (CRDs) have always thought that depression and other mood disorders can be a result of circadian rhythm misalignment or disruption, rather than a cause.
Now a review* suggests that polymorphisms in some of the 18 clock genes may cause both depression and CRDs.
- [T]reatment strategies or drugs aimed at restoring ‘normal’ circadian rhythmicity may be clinically useful.
- [W]e may predict that new antidepressant drugs will emerge that (…) target and correct abnormalities in the circadian timing system.
A recent careful study of patients with delayed sleep phase syndrome (DSPS) showed that
- patients who also showed depressive symptoms had an even later peak in the 6-sulphatoxymelatonin rhythm than patients with no depression.
Even research on rodents provides evidence
- for a role of clock genes in behaviours that are relevant to mood disorders.
Much of the genetic info in this review goes way over my head, but this bit sounds reasonable:
- The endogenous rythmicity within the master biological clock in the brain … is generated by interlinked positive and negative feedback loops of gene transcription and translation. If there is to be a role of circadian rhythmicity in mood disorders then it almost certainly involves these genes….
I’m hoping that these ideas represent a turning point in circadian rhythm research. I hope that, here on in, the researchers search for realistic and practical treatments, as well as useful diagnostic tests, for CRDs.
* Kennaway, David J. (2010) Review: Clock genes at the heart of depression. Journal of Psychopharmacology Vol. 24 No. 5
The illustration is borrowed from a blogpost by Jeff Pruett.
Next post: 60. Charting the Course of N24