Delayed sleep-phase syndrome (DSPS), also known as delayed sleep-phase disorder (DSPD) or delayed sleep-phase type (DSPT), is a circadian rhythm sleep disorder, a chronic disorder of the timing of sleep, peak period of alertness, hormonal and other rhythms. People with DSPS tend to fall asleep well after midnight and also have difficulty waking up in the morning.

Karakteristik:

1. Sleep-onset and wake times that are intractably later than desired
2. Actual sleep-onset times at nearly the same daily clock hour
3. Little or no reported difficulty in maintaining sleep once sleep has begun
4. Extreme difficulty awakening at the desired time in the morning
5. A relatively severe to absolute inability to advance the sleep phase to earlier hours by enforcing conventional sleep and wake times.

Bedanya dengan orang yang normal:

People with normal circadian systems can generally fall asleep quickly at night if they slept too little the night before. Falling asleep earlier will in turn automatically advance their circadian clocks due to decreased light exposure in the evening. In contrast, people with DSPS are unable to fall asleep before their usual sleep time, even if they are sleep-deprived. Research has shown that sleep deprivation does not reset the circadian clock of DSPS patients, as it does with normal people.

Penyebab:

In most cases, it is not known what causes the abnormality in the biological clocks of DSPS patients. DSPS tends to run in families and a growing body of evidence suggests that the problem is associated with the hPer3 (human period 3) gene. There have been several documented cases of DSPS and non-24 hour sleep-wake syndrome developing after traumatic head injury.

Akibatnya:

Lack of public awareness of the disorder contributes to the difficulties experienced by DSPS patients, who are commonly stereotyped as undisciplined or lazy. Parents may be chastised for not giving their children acceptable sleep patterns, and schools rarely tolerate chronically late, absent, or sleepy students and fail to see them as having a chronic illness.

By the time DSPS sufferers receive an accurate diagnosis, they often have been misdiagnosed or labelled as lazy and incompetent workers or students for years. Misdiagnosis of circadian rhythm sleep disorders as psychiatric conditions causes considerable distress to patients and their families, and leads to some patients being inappropriately prescribed psychoactive drugs. For many patients, diagnosis of DSPS is itself a life-changing breakthrough.

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sumber : Wikipedia