Insomnia Disorder 363
Specify if:
Episodic:  Symptoms last at least 1 month but less than 3 months.
Persistent:  Symptoms last 3 months or longer.
Recurrent: Two (or more) episodes within the space of 1 year.
Note:  Acute and short-term insomnia (i.e., symptoms lasting less than 3 months but oth-
erwise meeting all criteria with regard to frequency, intensity, distress, and/or impairment)
should be coded as an other specified insomnia disorder.
Note.  The diagnosis of insomnia disorder is given whether it occurs as an independent
condition or is comorbid with another mental disorder (e.g., major depressive disorder),
medical condition (e.g., pain), or another sleep disorder (e.g., a breathing-related sleep dis-
order). For instance, insomnia may develop it s own course with some anxiety and depres-
sive features but in the absenc e of criteria being met for an y one mental disorder. Insomnia
may also manifest as a clinical feature of a more predominant ment al disorder . Persistent
insomnia may even be a risk factor for depression and is a common residual symptom af-
ter treatment for this condition. With comorb id insomnia and a mental disorder, treatment
may also need to target both conditions. Give n these different courses, it is often impossi-
ble to establish the precise nature of the rela tionship between these clinical entities, and
this relationship may change over time. Therefore, in th e presence of insomnia and a co-
morbid disorder, it is not ne cessary to make a causal attribution between the two condi-
tions. Rather, the diagnosis of insomnia disord er is made with concurrent specification of
the clinically comorbid conditions. A concurre nt insomnia diagnosis should only be con-