Handbook of Psychology

328 Insomnia

Behavioral Assessment Devices

Several behavioral assessment devices are increasingly used
to monitor sleep-wake patterns. These devices include a
switch-activated clock, a voice-activated recording system,
and wrist actigraphy. The “rst two devices use a timer
(activated by a handheld switch or by a vocal response to a pe-
riodic tone) to measure the time required to fall asleep. Wrist
actigraphy is currently the most widely used device for ambu-
latory data collection. This activity-based monitoring system
uses a microprocessor to record and store wrist activity along
with the actual clock time. Data are processed through micro-
computer software, and an algorithm is used to estimate sleep
and wake based on wrist activity. The presence of motor ac-
tivity is interpreted as wakefulness and the absence of activity
is interpreted as sleep. This device, as well as other behavioral
assessment devices, does not measure sleep stages. Despite
these limitations, wrist actigraphy is a useful complementary
method for assessing insomnia and certain circadian rhythm
sleep disorders (Sadeh, Hauri, Kripke, & Lavie, 1995).

The Role of Psychological Evaluation

Because sleep disturbances often co-exist with psychopathol-
ogy, a psychological evaluation should be an integral compo-
nent of insomnia assessment. This assessment is necessary to
determine whether insomnia represents a primary disorder or
a disorder secondary to psychological disturbances. In the
latter case, treatment should initially target the underlying
psychological condition rather than the sleep problem. Also,
although most patients with insomnia do not meet diagnostic
criteria for serious psychiatric disorders (e.g., major depres-
sion, generalized anxiety disorder), almost all of them dis-
play some psychological distress (i.e., depressed and anxious
mood) concurrent to their sleep dif“culties. It is important to
quantify and monitor exacerbation or improvement of this
symptomatology during the course of treatment.
The most reliable strategy to determine the presence of
psychopathology is to incorporate into the clinical interview
key questions from the Structured Clinical Interview for
DSM(Spitzer, Williams, Gibbon, & First, 1990), along with
questions about past psychiatric history and treatment. This is
the most appropriate assessment modality when major psy-
chopathology is suspected. However, a more cost-effective
approach is to use brief screening instruments that target spe-
ci“c psychological features (e.g., emotional distress, anxiety,
depression) most commonly associated with insomnia com-
plaints. Instruments such as the Brief Symptom Inventory
(Derogatis & Melisaratos, 1983), the Beck Depression Inven-
tory(Beck, Ward, Mendelson, Mock, & Erbaugh, 1961), and

theState-Trait Anxiety Inventory (Spielberger, 1983) can

yield valuable screening data about psychological symptoms,

although none of these self-report measures should be used

alone to make a diagnosis. Psychometric screening should al-

ways be complemented by a clinical interview.

Evaluation of Daytime Sleepiness

Assessment of daytime sleepiness is essential when daytime

vigilance is compromised by a sleep disorder. The •gold stan-

dardŽ for this evaluation is the Multiple Sleep Latency Test

(MSLT), a laboratory-based procedure conducted during day-

time. It involves measuring the latency to sleep onset at “ve

20-minute nap opportunities occurring at two-hour intervals

throughout the day. Latency to sleep onset provides an objec-

tive measure of sleepiness. A mean sleep latency of less than

5 minutes is considered pathological. In comparison, (well

rested) individuals without sleep disorders usually take

10 minutes or more to fall asleep or do not fall asleep at all. Al-

though individuals with insomnia often complain about fa-

tigue, they do not show signi“cant sleepiness on the MSLT,

most likely because of their underlying hyperarousal state both

at night and during the day. The MSLT is used mostly with pa-

tients who suffer from other sleep disorders such as narcolepsy

and sleep apnea. It is an excellent measure to determine func-

tional impairments due to excessive daytime sleepiness.

Self-report questionnaires are also used to obtain subjec-

tive measures of daytime sleepiness. The Epworth Sleepiness

Scale (Johns, 1991) is an eight-item global and retrospective

measure assessing the likelihood of falling asleep in several

situations (e.g., watching TV, driving). It is also possible to as-

sess subjective sleepiness at a speci“c moment in time using

the Stanford Sleepiness Scale, a 7-point Likert scale (1

•feeling alert; wide awakeŽ 7 •sleep onset soon; lost strug-

gle to remain awakeŽ) re”ecting increasing levels of sleepi-

ness (Hoddes, Zarcone Smythe, Phillips, & Dement, 1973).

In this section, several methods of sleep assessment

were described with their relative strengths and weaknesses.

The choice of assessment strategies depends on the goal of the

evaluation. A multifaceted assessment combining a clinical

interview with the use of objective (e.g., polysomnography)

and subjective (e.g., sleep diary, self-report scales) measures

is ideal. However, polysomnography is not always necessary,

especially when the clinician has no suspicion about the pres-

ence of an underlying sleep disorder such as sleep apnea.

TREATMENTS

Despite its high prevalence and negative impact, insomnia re-

mains for the most part untreated. Estimates from the