Circadian rhythm sleep disorder, delayed sleep phase type

This code represents a chronic sleep disorder characterized by a persistent inability to fall asleep and wake up at socially conventional times, with a delay of at least two hours compared to desired times. Individuals with this condition typically have a normal sleep duration and quality once sleep is initiated, but their sleep-wake cycle is shifted later.

Use this code when documentation clearly indicates a diagnosis of delayed sleep phase syndrome (DSPS) or delayed sleep-wake phase disorder (DSWPD). This diagnosis is typically supported by a detailed sleep history, sleep diary, and sometimes actigraphy, demonstrating a consistent pattern of delayed sleep onset and offset.

• Ensure the documentation specifies "delayed sleep phase type" to differentiate from other circadian rhythm sleep disorders.
• Do not confuse with insomnia (F51.01) if the patient's primary issue is the timing of sleep, not the inability to initiate or maintain it once the delayed schedule is followed.
• Consider co-occurring mental health conditions (e.g., depression, anxiety) that may exacerbate or be associated with DSPS, and code them separately if documented.