362 Sleep-Wake Disorders
2nd Edition (ICSD-2) elaborated numerous diagnostic subtypes. DSM-IV was prepared for
use by mental health and general medical clinicians who are not experts in sleep medicine.
ICSD-2 reflected the science and opinions of  the sleep specialist community and was pre-
pared for use by specialists. 
The weight of available evidence supports the superior performance characteristics
(interrater reliability, as well as convergent, discriminant, and face validity) of simpler, less-
differentiated approaches to diagnosis of sleep-wake disord ers. The text accompanying
each set of diagnostic criteria provides linka ges to the corresponding disorders included in
ICSD-2. The DSM-5 sleep-wake disorders classif ication also specifies corresponding non-
psychiatric listings (e.g., ne urology codes) from the International Classification of Diseases
(ICD).
The field of sleep disorders medicine has progressed in this direction since the publi-
cation of DSM-IV. The use of biological validators is now embodied in the DSM-5 classi-
fication of sleep-wake disorder s, particularly for disorders of  excessive sleepiness, such as
narcolepsy; for breathing-rela ted sleep disorders, for whic h formal sleep studies (i.e.,
polysomnography) are indicated; and for rest less legs syndrome, which can often coexist
with periodic limb movements during sleep, detectable via polysomnography.
Insomnia Disorder
Diagnostic Criteria 307.42 (F51.01)
A. A predominant complaint of dissatisfaction with sleep quantity or quality, associated
with one (or more) of the following symptoms:
1. Difficulty initiating sleep. (In children, this may manifest as difficulty initiating sleep
without caregiver intervention.)
2. Difficulty maintaining sleep, characterized by frequent awakenings or problems re-