With Delayed Sleep Phase disorder (DSPD), the individual’s preferred sleep time is delayed three to six hours, compared to conventional times. DSPD is characterized by an inability to fall asleep at a desired, conventional clock time and awaken at a socially acceptable morning time. An alternative name for the disorder is: “circadian rhythm sleep disorder, delayed sleep phase type.”
When allowed to choose their preferred sleep schedule, patients with DSPD exhibit sleep of normal quality and duration for their age and maintain a stable (but delayed) relationship of entrainment to the 24-hour, sleep-wake pattern.1 2 3
Fig 5.1 — Advanced and delayed sleep phase4
1. Reid KJ and Zee PC. “Circadian disorders of the sleep-wake cycle,” in Kryger M, Roth T, Dement W (ed.), Principles and Practice of Sleep Medicine (5th Edition), St. Louis: Elsevier Saunders, 2011, pages 470-482.
2. Weitzman ED, Czeisler CA, Coleman RM, et al. Delayed sleep phase syndrome: a chronobiological disorder with sleep onset insomnia. Arch Gen Psychiatry. 1981;38:737-746.
3. Pelayo RP, Thorpy M, Glovinsky P. Prevalence of delayed sleep phase syndrome among adolescents. J Sleep Res. 1988;17:392.
4. Reid KJ and Zee PC. “Circadian disorders of the sleep-wake cycle,” in Kryger M, Roth T, Dement W (ed.), Principles and