Advanced sleep phase disorder | |
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Classification and external resources | |
Specialty | Psychiatry |
ICD-10 | G47.22 |
ICD-9-CM | 327.32 |
MeSH | D020178 |
Advanced sleep phase disorder (ASPD), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder or advanced sleep phase syndrome (ASPS), is a condition in which patients feel very sleepy and go to bed early in the evening (e.g. 6:00–8:00 p.m.) and wake up very early in the morning (e.g. around 3:00 a.m.).
People with ASPD are unable to stay awake until their desired bedtime and unable to stay asleep until their desired waking time. They will complain to a sleep clinician of early morning insomnia and falling asleep early in the evening. When someone has advanced sleep phase disorder their melatonin levels and core body temperature will cycle hours earlier than an average person. These symptoms must be present for at least three months in order to be correctly diagnosed.
ASPD is a rare disorder. It affects both men and women equally and has been determined to have a strong genetic link with 40–50% of people related to someone with ASPD having it themselves. As stated below, several genes have been discovered to have links with this syndrome and the body's circadian rhythms. Although it can be impairing, the syndrome is not necessarily unhealthy; most people don't seek help unless it starts to severely impact their social life.
Once diagnosed, ASPD can be treated with bright light therapy in the evenings or behaviorally with chronotherapy. Unlike other sleep disorders, ASPD does not disrupt normal functioning at work during the day and the patient does not complain of excessive daytime sleepiness. If their ASPD is causing people to lose out on evening activities, including putting their own normal children to bed, they may be able to force themselves to stay up later than their circadian rhythm requires. A sufferer of ASPD will still wake up very early and if this cycle continues it can lead to chronic sleep deprivation and other sleep disorders.
In 1999, Louis Ptáček's and Ying-Hui Fu's research group at the University of California, San Francisco reported findings of a human circadian rhythm disorder showing a familial tendency. The disorder was characterized by a lifelong pattern of sleep onset around 7:30 p.m. and offset around 4:30 a.m. Among three lineages, 29 people were identified as affected with this familial advanced sleep-phase disorder (FASPD), and 46 were considered unaffected. The pedigrees demonstrated FASPD to be a highly penetrant, autosomal dominant trait.