Delayed Sleep Phase Disorder

Delayed Sleep Phase Disorder

Delayed sleep-phase disorder (DSPD), also known as delayed sleep-phase syndrome (DSPS) or delayed sleep-phase type (DSPT), is a circadian rhythm sleep disorder affecting the timing of sleep, peak period of alertness, the core body temperature rhythm, hormonal and other daily rhythms, compared to the general population and relative to societal requirements. People with DSPD generally fall asleep some hours after midnight and have difficulty waking up in the morning.

Often affected people report that while they do not get to sleep until the early morning they do fall asleep around the same time every day. Unless they have another sleep disorder such as sleep apnea in addition to DSPD, patients can sleep well and have a normal need for sleep. However, they find it very difficult to wake up in time for a typical school or work day. If, however, they are allowed to follow their own schedules, e.g. sleeping from 4 a.m. to noon (04:00 to 12:00), they sleep soundly, awaken spontaneously, and do not experience excessive daytime sleepiness.

The syndrome usually develops in early childhood or adolescence. An adolescent version disappears in adolescence or early adulthood; otherwise DSPD is a lifelong condition. Depending on the severity, the symptoms can be managed to a greater or lesser degree, but there is no all-encompassing cure. Prevalence among adults, equally distributed among women and men, is approximately 0.15%, or 3 in 2,000. It is also genetically linked to ADHD by findings of polymorphism in genes in common between those apparently involved in ADHD and those involved in the circadian rhythm and a high proportion of DSPD among those with ADHD.

DSPD was first formally described in 1981 by Dr. Elliot D. Weitzman and others at Montefiore Medical Center. It is responsible for 7–10% of patient complaints of chronic insomnia. However, as few doctors are aware of it, it often goes untreated or is treated inappropriately; DSPD is often misdiagnosed as primary insomnia or as a psychiatric condition. DSPD can be treated or helped in some cases by careful daily sleep practices, light therapy, and medications such as melatonin and modafinil (Provigil); the former is a natural neurohormone responsible partly and in tiny amounts for the human body clock. At its most severe and inflexible, it is a disability.