Chapter 028. Sleep Disorders (Part 7) potx

Chapter 028. Sleep Disorders
(Part 7)

Psychophysiologic Insomnia
Persistent psychophysiologic insomnia is a behavioral disorder in which
patients are preoccupied with a perceived inability to sleep adequately at night.
This sleep disorder begins like any other acute insomnia; however, the poor sleep
habits and sleep-related anxiety ("insomnia phobia") persist long after the initial
incident. Such patients become hyperaroused by their own efforts to sleep or by
the sleep environment, and the insomnia becomes a conditioned or learned
response. Patients may be able to fall asleep more easily at unscheduled times
(when not trying) or outside the home environment. Polysomnographic recording
in patients with psychophysiologic insomnia reveals an objective sleep
disturbance, often with an abnormally long sleep latency; frequent nocturnal
awakenings; and an increased amount of stage 1 transitional sleep. Rigorous
attention should be paid to improving sleep hygiene, correction of
counterproductive, arousing behaviors before bedtime, and minimizing
exaggerated beliefs regarding the negative consequences of insomnia. Behavioral
therapies are the treatment modality of choice, with intermittent use of
medications. When patients are awake for >20 min, they should read or perform
other relaxing activities to distract themselves from insomnia-related anxiety. In
addition, bedtime and wake time should be scheduled to restrict time in bed to be
equal to their perceived total sleep time. This will generally produce sleep
deprivation, greater sleep drive, and, eventually, better sleep. Time in bed can then
be gradually expanded. In addition, methods directed towards producing
relaxation in the sleep setting (e.g., meditation, muscle relaxation) are encouraged.

Adjustment Insomnia (Acute Insomnia)

This typically develops after a change in the sleeping environment (e.g., in
an unfamiliar hotel or hospital bed) or before or after a significant life event, such

as a change of occupation, loss of a loved one, illness, or anxiety over a deadline
or examination. Increased sleep latency, frequent awakenings from sleep, and
early morning awakening can all occur. Recovery is generally rapid, usually
within a few weeks. Treatment is symptomatic, with intermittent use of hypnotics
and resolution of the underlying stress. Altitude insomnia describes a sleep
disturbance that is a common consequence of exposure to high altitude. Periodic
breathing of the Cheyne-Stokes type occurs during NREM sleep about half the
time at high altitude, with restoration of a regular breathing pattern during REM
sleep. Both hypoxia and hypocapnia are thought to be involved in the development
of periodic breathing. Frequent awakenings and poor quality sleep characterize
altitude insomnia, which is generally worse on the first few nights at high altitude
but may persist. Treatment with acetazolamide can decrease time spent in periodic
breathing and substantially reduce hypoxia during sleep.

Comorbid Insomnia
Insomnia Associated with Mental Disorders

Approximately 80% of patients with psychiatric disorders describe sleep
complaints. There is considerable heterogeneity, however, in the nature of the
sleep disturbance both between conditions and among patients with the same
condition.
Depression can be associated with sleep onset insomnia, sleep maintenance
insomnia, or early morning wakefulness. However, hypersomnia occurs in some
depressed patients, especially adolescents and those with either bipolar or seasonal
(fall/winter) depression (Chap. 386). Indeed, sleep disturbance is an important
vegetative sign of depression and may commence before any mood changes are
perceived by the patient.
Consistent polysomnographic findings in depression include decreased
REM sleep latency, lengthened first REM sleep episode, and shortened first
NREM sleep episode; however, these findings are not specific for depression, and

the extent of these changes varies with age and symptomatology. Depressed
patients also show decreased slow-wave sleep and reduced sleep continuity.
In mania and hypomania, sleep latency is increased and total sleep time can
be reduced. Patients with anxiety disorders tend not to show the changes in REM
sleep and slow-wave sleep seen in endogenously depressed patients. Chronic
alcoholics lack slow-wave sleep, have decreased amounts of REM sleep (as an
acute response to alcohol), and have frequent arousals throughout the night. This is
associated with impaired daytime alertness.
The sleep of chronic alcoholics may remain disturbed for years after
discontinuance of alcohol usage. Sleep architecture and physiology are disturbed
in schizophrenia (with a decreased amount of stage 4 sleep and a lack of
augmentation of REM sleep following REM sleep deprivation); chronic
schizophrenics often show day-night reversal, sleep fragmentation, and insomnia.