Patients with delayed sleep-wake phase disorder (DSWPD) and non-24-hour sleep-wake disorder (N24SWD) have longer biological circadian rhythms compared with controls; and non-delayed DSWPD patients potentially show dysfunction between biological rhythms and behavioral sleep periods, or conditioned sleep onset insomnia.
Why this matters
DSWPD and N24SWD are sleep/wake cycle (circadian)-based sleep disorders. In DSWPD, circadian rhythms are either delayed by approximately 3 or more hours or have normal timings but abnormal sleep behavioral rhythms, and in N24SWD they cannot be synchronized to the 24–hour light-dark cycle, resulting in significantly longer than 24-hour sleep/wake cycles.
Greater understanding of the circadian taus involved in DSWPD and N24SWD, which have a significant impact on daily functioning, has important implications for the management of these conditions.