In a study published in the October issue of the journal Sleep, Northwestern University researchers reported that melatonin was most effective in resetting the body's internal, or circadian, clock when it was timed to the individual's sleep patterns.
The study included patients who habitually went to sleep very late at night and had difficulty waking up when they needed to in the morning. They reported difficulty falling asleep at conventional bedtimes.
When this occurs because of disturbances in circadian rhythms it is known as delayed sleep phase syndrome (DSPS).
"This is a fairly common problem that can have a tremendous impact on school and work performance and all aspects of a person's life," researcher Margarita Dubocovich, PhD, tells WebMD. The study notes that about 10% of people with insomnia may have DSPS.
Setting the Stage for Sleep
Circadian rhythm disorders are disruptions in the body clock that regulates when a person wakes and sleeps over the course of a 24-hour day. Jet lag, shift work, medications, and changes in routine can all disrupt the body's internal clock, but no obvious external influences exist in people with DSPS.
Melatonin is a hormone produced naturally by the brain to regulate sleep. In most people levels increase in the evening, setting the stage for sleep.
While some studies have shown melatonin supplements to be effective for treating circadian rhythm disorders like DSPS, the timing of treatment has not been well understood.
Furthermore, there is no evidence supporting the use of melatonin in treating insomnia, according to a report from the Agency for Healthcare Research and Quality.
In the newly published study of 13 people, Dubocovich found that melatonin worked best when treatment times were determined by the patient's individual sleep schedule. There was no significant effect on sleep onset or offset (how early they awakened from sleep).
"Melatonin works in two ways," Dubocovich says. "If you only want to induce sleep you can take it about two hours before you want to go to sleep."
She warned, however, that people with sleep problems should not self-medicate with melatonin.
"This is all very complicated," she says. "If you give melatonin at the right time of day it can be effective. But if you give it at the wrong time it can make sleep problems worse."
Sleep medicine specialist Steven W. Lockley, PhD, agrees. In an editorial accompanying the paper, Lockley wrote that identifying the individual patient's biological sleep patterns is an important challenge for the diagnosis and treatment of circadian rhythm sleep disorders.
Lockley is with the Harvard Medical School Division of Sleep Medicine.
"It is clear that both the duration and the timing of sleep are important," Lockley tells WebMD. "If you can't get to sleep at the right time you don't tend to sleep very well. That is true for people with delayed sleep phase syndrome and for everyone."