National Sleep Foundation

Chapter 5: Circadian Rhythm Sleep Disorders

A Case Study in Delayed Sleep Phase Type

John, a 17-year-old high school student, was referred to the sleep center with the complaint of not being able to fall asleep.

Patient History and Examination

History of Previous Illness: John reports a history of difficulty falling asleep at night that has been present from grade school but has drastically worsened during the past 2 years. He has always been a "night owl" and throughout grade school would resist his bed time and have difficulty waking up in the morning. He was often caught reading in bed with a flashlight after "lights out."

Past Medical History: None significant.

Social History: John was a competent student until about 2 years ago, at which point his grades began to decline. When awakened by his parents, John gets to school on time but falls asleep in his morning classes. If left asleep, he does not awaken until around 1:00 PM and then does not bother to go to school. John is currently on the verge of being expelled from school due to frequent unexplained absences.

Family History: Patient’s father had a similar behavior pattern at John's age.

Review of Sleep Pattern: Typically, John does not fall asleep until 5:00 AM. He sleeps deeply until 7:00 AM, when his parents awaken him for school. His parents report he often surfs the Internet until after 2:00 AM.

Evaluation and Diagnosis
After ruling out other sleep disorders (e.g., sleep-onset insomnia associated with psychological issues) and reviewing a 2-week sleep diary, the patient was diagnosed with delayed sleep-phase disorder.

Treatment and Follow-up
The patient was instructed to get up regularly at noon and undergo 45 minutes of "light therapy" by going outside without sunglasses. In addition, 3 mg of melatonin was prescribed to be taken at 1:00 AM. John was further advised to limit his exposure to bright light after 4:00 PM by wearing wrap-around sun glasses. Each week, the bright light therapy and the melatonin were prescribed to be taken 1 hour earlier until an acceptable wake-up time was achieved (for John, this was 9:00 AM). John’s class schedule was rearranged so that he would start classes in the afternoon and would end the day with a private tutor for the classes he missed in the morning. This tutor would be phased out as John’s wake time advanced. Using this approach, John was able to graduate 6 months after his classmates.

Currently (5 years after starting treatment), John gets up at 10:00 AM for 30 minutes of outdoor light therapy. He works an afternoon/evening job and takes night classes at a local college. He still struggles occasionally with his delayed sleep phase disorder, especially when he does not get light therapy for a few days or when he stays out late on the weekend.