Teens Who Can't Sleep: Insomnia or Circadian Rhythm Disorder?

Maggie is a 16-year-old girl who came to see me because she wanted help with her longstanding difficulties falling asleep at night and waking up in the morning. She goes to bed between midnight and 3 am and usually lies awake worrying until falling asleep at 3 to 4 am. She often video-calls or texts her boyfriend before sleep. Her wakeup time is 8 am; she typically wakes exhausted, having slept 4 to 5 hours. Although a good student, she is often late for classes. On weekends, she wakes around noon. She is tired, anxious, and demoralized. She cannot concentrate as well as she did prior to the onset of her sleep symptoms at age 10 to 11 years. Her psychiatric history includes a diagnosis of anxiety and depression, both in remission, treated with fluoxetine 30 mg daily for several years. Difficulties falling asleep and waking in the morning are common complaints among adolescents and young adults. Before my additional year of training in sleep medicine, I would have misdiagnosed Maggie as having insomnia rather than delayed sleep phase disorder (DSPD), a circadian rhythm disorder.