The disorder affects the timing of biological rhythms including sleep, peak period of alertness, core body temperature, and hormonal cycles.

In one example, several dozen volunteers spent many months underground in a French cave, while researchers monitored their periods of waking and sleeping.

Symptom management may be possible with therapeutic drugs such as orexin antagonists or melatonin receptor agonists, as well as regular outdoor exercise.

People with DSPD may improve their quality of life by choosing careers that allow late sleeping times, rather than forcing themselves to follow a conventional 9-to-5 work schedule.

Sleep researcher Michael Terman has suggested that those who follow their internal circadian clocks may be less likely to have depression than those trying to live on a different schedule.

[24] The altered phase relationship between the timing of sleep and the circadian rhythm of body core temperature has been reported previously in DSPD patients studied in entrained conditions.

In normal subjects, the phase relationship between sleep and temperature changes in temporal isolation relative to that observed under entrained conditions: in isolation, temperature minimum tends to occur toward the beginning of sleep, whereas under entrained conditions, temperature minimum occurs toward the end of the sleep period—a change in phase angle of several hours; DSPD patients may have a reduced capacity to achieve such a change in phase angle in response to entrainment.

[25] Possibly as a consequence of these altered internal phase relationships, that the quality of sleep in DSPD may be substantially poorer than that of normal subjects, even when bedtimes and wake times are self-selected.

This finding may suggest that, in addition to abnormal circadian clock function, DSPD may be characterized by alteration(s) in the homeostatic regulation of sleep, as well.

Falling asleep earlier will in turn automatically help to advance their circadian clocks due to decreased light exposure in the evening.

Sleeping late on weekends, and/or taking long naps during the day, may give people with DSPD relief from daytime sleepiness.

DSPD patients who have tried using sedatives at night often report that the medication makes them feel tired or relaxed, but that it fails to induce sleep.

As the disorder occurs in childhood and is most common in adolescence, it is often the patient's parents who initiate seeking help, after great difficulty waking their child in time for school.

[38] The photopigment of the retinal photosensitive ganglion cells, melanopsin, is excited by light mainly in the blue portion of the visible spectrum (absorption peaks at ~480 nanometers).

Side effects of melatonin may include sleep disturbance, nightmares, daytime sleepiness, and depression, though the current tendency to use lower doses has decreased such complaints.

[citation needed] A review by the US Department of Health and Human Services found little difference between melatonin and placebo for most primary and secondary sleep disorders.

[50] Modafinil (brand name Provigil) is a stimulant approved in the US for treatment of shift-work sleep disorder, which shares some characteristics with DSPD.

Caffeine and other stimulant drugs to keep a person awake during the day may not be necessary and should be avoided in the afternoon and evening, in accordance with good sleep hygiene.

Some other careers that have an emphasis on early morning work hours, such as bakers, coffee baristas, pilots and flight crews, teachers, mail carriers, waste collection, and farming, can be particularly difficult for people who naturally sleep later than is typical.

[55] Rehabilitation for DSPD patients includes acceptance of the condition and choosing a career that allows late sleeping times or running a home business with flexible hours.

It is imperative that physicians recognize the medical condition of SWSD disability in their patients and bring it to the notice of the public institutions responsible for vocational and social rehabilitation.

[55]In the United States, the Americans with Disabilities Act requires that employers make reasonable accommodations for employees with sleeping disorders.

[57] Lack of public awareness of the disorder contributes to the difficulties experienced by people with DSPD, who are commonly stereotyped as undisciplined or lazy.

By the time DSPD sufferers receive an accurate diagnosis, they often have been misdiagnosed or labelled as lazy and incompetent workers or students for years.

[58][59][60] People with DSPD who force themselves to follow a normal 9–5 workday "are not often successful and may develop physical and psychological complaints during waking hours, e.g., sleepiness, fatigue, headache, decreased appetite, or depressed mood.

Patients with circadian rhythm sleep disorders often have difficulty maintaining ordinary social lives, and some of them lose their jobs or fail to attend school.

[61] Using the ICSD-1 diagnostic criteria (current edition ICSD-3) a study by telephone questionnaire in 1993 of 7,700 randomly selected adults (aged 18–67) in Norway estimated the prevalence of DSPD at 0.17%.

[61] A 2014 study of 9100 New Zealand adults (age 20–59) using a modified version of the Munich Chronotype Questionnaire found a DSPD prevalence of 1.5% to 8.9% depending on the strictness of the definition used.

[62] A 2002 study of older adults (age 40–65) in San Diego found 3.1% had complaints of difficulty falling asleep at night and waking in the morning, but did not apply formal diagnostic criteria.

According to Mary Carskadon, both circadian phase and homeostasis (the accumulation of sleep pressure during the wake period) contribute to a DSPD-like condition in post-pubertal as compared to pre-pubertal youngsters.