Researchers search for cause of delayed sleep phase syndrome

July 11, 2003

CHICAGO-Two new research studies to determine the cause of Delayed Sleep Phase Syndrome (DSPS), a serious sleep disorder thought to affect between 500,000 and several million Americans, are being undertaken by researchers at Rush-Presbyterian-St. Luke's Medical Center.

People with DSPS are unable to fall asleep until several hours past their preferred bedtime and have difficulty waking up in the morning to begin normal activities. It is one of six disorders of the circadian rhythm, indicating a malfunction within the body's internal 24-hour clock.

Unlike traditional sleep-onset insomnia, DSPS patients are able to fall asleep quickly and stay asleep for a normal eight-hour period, but this occurs at a much-delayed hour. The consequences for people with DSPS are that they are often late for jobs and school in the morning, or too sleepy during the day to be productive.

The National Institute of Mental Health is funding two studies directed by Dr. James K. Wyatt, assistant professor of psychology and laboratory director of the Sleep Disorders Center at Rush. The first study will measure amounts of the hormone melatonin found in saliva, which is activated at night, on three separate occasions. Daily light exposure and sleep/wake patterns will also be measured.

In this study, Wyatt and his colleagues will assess 10 volunteers between the ages 18 and 30. The information collected in this study will help determine the variability in symptom severity over time.

The second study will require volunteers to stay in the Rush Sleep Disorders Center for six consecutive days and evenings, allowing Wyatt and his colleagues to closely monitor the volunteer's sleep activity, mental performance during wakefulness and functioning of the body clock system.

The overall aim of the research is to lay the foundation to determine what influences the cause of DSPS-- behavioral, psychological or sociological issues.

"DSPS could be a social phenomenon because teens or young adults may see changes in their sleep patterns due to changes in school, homework or extra-curricular activities," Wyatt said. "It could also be a psychological phenomenon with more going on later in the night or it could be a biological phenomenon or any combination of the three."

DSPS typically arises during adolescence, but can appear in a person's twenties or thirties. DSPS can create serious problems in that oversleeping can result in missing the first few hours of the day's activities while a forced awakening leaves people sleep deprived.

Possible consequences of this syndrome include increased risk of motor-vehicle accidents, impaired academic performance, mood disturbance and greater use of substances to increase alertness, such as caffeine.

Rush is seeking people between the ages of 18 and 30 to participate in the study. Potential participants should call 312-563-4292 for more information.
Rush-Presbyterian-St. Luke's Medical Center includes the 824-bed Presbyterian-St. Luke's Hospital; 110-bed Johnston R. Bowman Health Center; Rush University (Rush Medical College, College of Nursing, College of Health Sciences and the Graduate College).

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