Winter Depression

Melatonin and Depression

Melatonin is an important night time hormone associated with sleep and regeneration. However, excessive levels or daytime melatonin can cause depressive disorders. Medical research confirms the relationship between melatonin and mood disorders. The following paragraphs explain how melatonin works and why it causes depression.

Darkness & Melatonin

Melatonin is normally released by the pineal gland in the evening as sunlight is diminishing. Melatonin causes us to feel tired and withdraw. This helps us to sleep, but if we have to be awake when melatonin is in our system, we become lethargic, disoriented, irritable and moody. This explains why shift work and jet lag can be so debilitating, and why depression rates are highest in darker climates. Almost everyone with a mood disorder suffers worse in the winter because of excess melatonin in his or her system.

Daytime Melatonin

Just as with jet lag, other factors can cause our bodies to produce melatonin into the day. Some causes such as trauma, stress, injury, age or lack of light will shift your body’s timing or release of melatonin. This shift can create excessive levels during the day and not enough melatonin at night. If you experience any of the following symptoms, you may have a melatonin imbalance:

  • Tiredness or lethargy during the day
  • Social or physical withdrawal
  • Irritability
  • Excessive sleepiness or insomnia

Specialised Light Supresses Melatonin

The release of melatonin is triggered by photoreceptors in the eye, called melanopsin. This is how darkness signals the brain to produce melatonin and stop the production of active, daytime hormones such as serotonin. However, when stimulated by special light, these same photoreceptors also tell the brain to stop the production of melatonin.


Symptoms, Diagnosis Tests and Treatment

Area for links to related pages...


CALL 0208 540 3389
FAX 0208 540 3389


  • Full Name
  • Mobile or Office Number
  • Place your message here