Seventy million people in the United States suffer from sleep disorders according to the National Sleep Foundation. About 40 million of these suffer from acute sleep disorders, including circadian rhythm sleep disturbance.

Consider Dan, a 23-year old male complaining of insomnia. He can't fall asleep at night and habitually arrives at work later than his employer's 8 a.m. starting time. Does Dan have depression, situational insomnia, obstructive sleep apnea or a circadian rhythm disturbance? Or does he just want to start work late?

"When someone claims he's constantly late to work due to chronic sleep problems, a doctor must eliminate other possibilities first," said Dr. Skip Freedman, executive medical director at AllMed Healthcare Management, a leading Independent Review Organization (IRO). (http://www.allmedmd.com/)

According to Freedman, circadian rhythm sleep disorder is a disturbance of a patient's sleep-wake cycle. Patients with circadian rhythm sleep disorders are unable to sleep or stay awake during work, school or social events. Circadian rhythm sleep disorders include jet lag, shift work sleep disorder, irregular sleep wake phase, advanced sleep phase disorder (ASPD) and delayed sleep disorder (DSPD).

Rule out other disorders

"Doctors need to decide whether patients like Dan don't like to go to work on time, are depressed, have situational insomnia or circadian rhythm sleep disturbance," said Freedman.

Once Dan's doctor rules out depression using a depression questionnaire, he can refer Dan to a sleep medicine specialist. Using a polysomnogram (sleep test), the specialist can check for other common sleep problems. Ruling them out, he can check Dan's circadian clock markers next.

One technique is to measure Dan's melatonin level, the hormone secreted by the pineal gland. Melatonin is the primary influencer of sleep and thus a sleep marker. During daylight, the gland produces less melatonin, because light suppresses melatonin production. As the light fades, the gland increases melatonin production to induce sleep.

Therapies for circadian disorders

Delayed sleep-phase syndrome and early sleep-phase syndrome are circadian rhythm disturbances treated by combining melatonin and phototherapy. Although phototherapy is standard of care for circadian disturbance, melatonin isn't FDA approved. However, it is available as a supplement in the United States.

In Dan's case, the specialists discovered his melatonin levels were low during the times he'd normally sleep. This signaled a delayed sleep phase, and Dan took off two weeks from work to receive treatment.

Working back about an hour each day, the doctor's treatment used melatonin to make Dan sleepy and exposed him to 2,500 lux of light for two to three hours. (Lux is a unit of brightness emitted by candle to the eye one meter away.) The treatment pushed back Dan's sleep-cycle pattern an hour a day for two weeks until he began falling to sleep at normal hours and could get to work on time.