rhythm and the sleep–wake schedule required by an individual’s physical environment
or social or professional schedule. 
B. The sleep disruption leads to excessive sleepiness or insomnia, or both.
C. The sleep disturbance causes clinically significant distress or impairment in social, oc-
cupational, and other important areas of functioning.
Coding note:  For ICD-9-CM, code 307.45 for all subtypes. For ICD-10-CM, code is based
on subtype.
Specify whether:
307.45 (G47.21) Delayed sleep phase type:  A pattern of delayed sleep onset and
awakening times, with an inability to fall asleep and awaken at a desired or convention-
ally acceptable earlier time.
Specify if:
Familial:  A family history of delayed sleep phase is present.
Specify if:
Overlapping with non-24-hour sleep-wake type:  Delayed sleep phase type
may overlap with another circadian rhythm sleep-wake disorder, non-24-hour
sleep-wake type. 
307.45 (G47.22) Advanced sleep phase type:  A pattern of advanced sleep onset and
awakening times, with an inability to remain awake or asleep until the desired or con-
ventionally acceptable later sleep or wake times.
Specify if:
Familial:  A family history of advanced sleep phase is present. 
307.45 (G47.23) Irregular sleep-wake type:  A temporally disorganized sleep-wake
pattern, such that the timing of sleep and wake periods is variable throughout the 24-
hour period.