nighttime sleep disturbances are distressed or have functional impairment. For example, sleep
continuity is often interrupted in healthy olde r adults who nevertheless identify themselves
as good sleepers. A diagnosis of insomnia disorder should be reserved for those individuals
with significant daytime distress or impairment related to their nighttime sleep difficulties.
Associated Features Supporting Diagnosis 
Insomnia is often associated  with physiological and cognitive arousal and conditioning
factors that interfere with sleep. A preoccupati on with sleep and distress due to the inabil-
ity to sleep may lead to a vicious cycle: the more the individual strives to sleep, the more
frustration builds and further im pairs sleep. Thus, excessive attention and efforts to sleep,
which override normal sleep-onset mechanisms, may contribute to the development of in-
somnia. Individuals with  persistent insomnia may also acquire maladapt ive sleep habits
(e.g., spending excessive time in bed; following an erratic sleep schedule; napping) and
cognitions (e.g., fear of sleeplessness; apprehensions of daytime impairments; clock mon-
itoring) during the course of the disorder. Engaging in such activities in an environment in
which the individual has frequently spent sleepless nights may further compound the con-
ditioned arousal and perpetuate sleep difficulties. Conversely, the individual may fall asleep
more easily when not trying to do so. Some individuals also report better sleep when away
from their own bedrooms and their usual routines. 
Insomnia may be accompanied by a variety of daytime complaints and symptoms, in-
cluding fatigue, decreased en ergy, and mood disturbances. Symptoms of anxiety or de-
pression that do not meet criteria for a specif ic mental disorder may be present, as well as
an excessive focus on the perceived effect s of sleep loss on daytime functioning. 
Individuals with inso mnia may have elevated scores on self-report psychological or