420 Sleep-Wake Disorders
suggest a diagnosis of sleep disorder associated with another medical condition. Con-
versely, sleep symptoms that appear only afte r the initiation of a particular medication/
substance suggest a substance/medication-ind uced sleep disorder. If the disturbance is
comorbid with another medical condition and is also exacerbated by substance use, both
diagnoses (i.e., sleep disorder associated with another medical condition and substance/
medication-induced sleep disorder) are given. When there is insuffici ent evidence to de-
termine whether the sleep distur bance is attributable to a substance/medication or to an-
other medical condition or is primary (i.e., not due to either a substance/medication or
another medical condition), a diagnosis of ot her specified sleep-wake disorder or unspec-
ified sleep-wake disorder is indicated.
Comorbidity
See the “Comorbidity” sections for other sleep  disorders in this chapter, including insom-
nia, hypersomnolence, centra l sleep apnea, sleep-related hypoventilation, and circadian
rhythm sleep-wake disorders, shift work type.
Relationship to Internat ional Classification of 
Sleep Disorders
The International Classifica tion of Sleep Disorders, 2nd Edition (ICSD-2), lists sleep disorders
“due to drug or substance” under their respective phenotypes (e.g., insomnia, hypersomnia).
Other Specified Insomnia Disorder
780.52 (G47.09)
This category applies to presentations in which symptoms characteristic of insomnia disorder
that cause clinically significant distress or impairment in social, occupational, or other important
areas of functioning predominate but do not meet th e full criteria for insomnia disorder or any
of the disorders in the sleep-wake disorders diagnostic class. The other specified insomnia dis-