Melatonin is a naturally occurring hormone synthesized in the pineal gland from serotonin. It plays a vital role in maintaining the natural cycle of sleep and wakefulness. For this reason, it is often taken to alleviate jet lag. There is some controversy, however, over whether or not melatonin can worsen symptoms of depression.
Depression and Menstruation
A few studies have shown that melatonin has worsened depression in some people. However, these studies are not without their critics, who claim the studies were flawed by small sample sizes. Melatonin is also known to cause an increase in prolactin, a hormone that plays a role in producing milk and in regulating the menstrual cycle. Since women experience twice the rate of depression as men and the causes are thought to be related to hormonal cycles, women who are at risk for depression and who experience mood changes related to menstruation may wish to avoid it.
Seasonal Affective Disorder
Circadian rhythms are biological cycles, roughly 24 hours in length, that govern certain biological processes. For example, your body produces hormones like cortisol in the morning, when you need to get up, and releases melatonin at night, when you need to go to sleep. These rhythms are altered by the presence or absence of light.
Depression occurring during the winter months, known as seasonal affective disorder, or SAD, is thought to be caused by a disruption of circadian rhythms brought on by an absence of light. The National Institute of Mental Health reports that melatonin supplementation is an effective treatment for this form of depression. The timing of the dose has to be adjusted to the individual's own rhythms: some people do better if melatonin is administered in the early morning, while others do better if it is given in mid-afternoon.
Perimenopause and Menopause
A 2001 study published in "Experimental Gerontology" found that perimenopausal and menopausal women receiving melatonin expressed higher levels of well-being and reported lower levels of depression than similar women not receiving melatonin. Measures of hormones that usually increase among women nearing menopause, luteotropic hormone and follicle stimulating hormone, decreased among the perimenopausal women receiving melatonin. This result suggests that melatonin may restore female hormonal levels to a more youthful pattern.
Drugs and Melatonin Receptors
An additional line of evidence that melatonin can worsen depression in some people is found in studies of certain prescription sleep aids. While these sleep aids do not contain melatonin, they do bind to melatonin receptors in the brain. Drugs.com, which summarizes peer-reviewed research on medication, reports that approximately 2 percent of people using ramelteon, which is sold as Rozerem, experience worsened depression. While depression is a rare side effect, when it does occur it can be severe. One patient wrote, "Severe depression, stayed in bed and slept for three days, crying, suicidal, a complete mess." This drug also increases levels of the hormone prolactin, which, in excess, can cause feelings of anger and hostility in women.
On the other hand, scientists are now testing a new antidepressant that binds to melatonin receptors. Preliminary results, published in 2010 in "CNS Neuroscience & Therapeutics," suggest that it reduces depression, causes a moderate improvement in sleep and has a favorable side-effects profile.
Considerations
If you believe you would benefit from more melatonin but hesitate to take it in pill form, you can take steps to increase your body's own production of melatonin. Expose yourself to bright light early in the morning. Eat foods rich in tryptophan, an amino acid precursor of melatonin, and vitamin B-6, which your body needs in order to convert this substance into serotonin and then to melatonin. Avoid caffeine, nicotine and alcohol, which can decrease melatonin levels. Sleep in total darkness at night to stimulate its release.
A common-sense course of action is for people with a history of depression to avoid taking any medication, even one sold over the counter or in health food stores, without first consulting a doctor. Patients with depression should also make sure that any doctor prescribing medication knows about their medical history. If you are prone to depression, It is also useful to read the package inserts found in all prescribed drugs and to avoid taking anything that lists depression as a side effect.
References
- University of Maryland Medical Center: Melatonin
- "CNS Neuroscience & Therapeutics"; Melatonin Receptor Agonists: New Options for Insomnia and Depression Treatment; G. Spadoni, et al.; September 15, 2010
- National Institute of Mental Health: Properly Timed Light, Melatonin Lift Winter Depression by Syncing Rhythms
- Ask a Patient: Drug Ratings for Rozerem
- "Experimental Gerontology" Effects of Melatonin In Perimenopausal and Menopausal Women: A Randomzed and Placebo Controlled Study; G. Bellipanni, et al.; January 2001
- National Sleep Foundation: Melatonin and Sleep
