Table 1. Overview of clinical features and treatment of circadian rhythm sleep disorders (CRSD) ^*.

Disorder	Clinical Features	Treatment
Delayed leep phase disorder (DSPD)	Stable delay of the major sleep period, resulting in difficulty falling asleep at night and difficulty waking up in the monring	Bright ight therapy 2,000-2:500 lux for 2 hours at or 2-3hours prior to habitual rise time 0.5 mg-3mg melatonin 5-7h prior to steep time
Advanced sleep phase disorder (ASPD)	Stable advance of the major sleep period, resulting in difficulty staying awake in the evening and difficulty maintaining asleep in the morning	Bright light therapy 2,000-2,500 iux for 2h in evening (around 7-9pm)
Non-24 Hour Sleep Wake Disorder (N24HSWD)	Chronic and steady 1 to 2 hours daily delay of sleep and wake schedule resutting in insomnia, difficulty waking up in the morning and excessive daytime sleepiness	Blind - 0 5mg melatonin 1h before preferred bedtime. Sighted - morning bright light therapy at rise time and/or night melatonin administration
Irregular Sleep-Wake Rhythm (ISWR)	Absence of a clearly discernable sleep-wake circadian rhythm resulting in insomnia and/or excessive daytime sleepiness	Increase daytime light exposure and social activity Minimize nighttime light and noise exposure Evening melatonin administration combined with daytime light exposure

^*Sleep hygiene is an important component to treat CRSD.