Insomnia Insomnia

68 Attarian
showed similar degrees of sleep impairment. Psychologically, however, patients
with persistent psychophysiological insomnia were similar to normal sleepers and
different from dysthymic patients, except that psychophysiological patients were
more likely to be repressors or sensation avoiders than normal subjects. Additionally,
psychophysiological patients suffered more than either normal subjects or
dysthymics from tension-related symptoms such as muscle tension headaches (7).
EPIDEMIOLOGY
The exact incidence and prevalence of psychophysiological insomnia is unknown.
In a study of 216 patients with insomnia from five centers, psychophysiological
insomnia was the primary diagnosis in 12.5% of all cases and a secondary
diagnosis in another 27.2% (8). A different study found that of 113 subjects complaining
of insomnia, 11.3% had psychophysiological insomnia (9). According to a
third study of 8000 patients seeking help for insomnia at multiple sleep centers,
about 15% were diagnosed with psychophysiological insomnia (10). Psychophysiological
insomnia is often diagnosed as a secondary problem because learned associations
often prevent or disrupt sleep in many other forms of chronic insomnia.
ETIOLOGY
A few nights of disturbed sleep due to stress such as psychological distress,
physical pain, or any other acute internal or external event, is a universal human
experience. In other words, anyone can have a few bad nights of sleep. In the
majority of cases, the trouble is short-lived. People suffering from psychophysiological
insomnia, however, continue to have poor sleep despite the resolution of
the acute event. In the development of pyschophysiological insomnia there are three
factors playing a role:
1. Predisposition: being an excessive worrier (11), being physiologically hyperaroused
(12), and familial inheritance of the tendency to develop insomnia (13).
2. Precipitant: a transient stressor.
3. Perpetuating factors: the individual’s expectation of a poor night’s sleep that becomes
a self-fulfilling prophecy and the counterproductive trials to sleep (11).
In some patients with psychophysiological insomnia, either a precipitant is not
found or the stressor is so minor that it has been forgotten. Rather, poor sleep may
have gradually developed as an occasionally occurring disturbed night leads to
increased concern, causing sleep to deteriorate in a snowball fashion, until it
becomes the patient’s chief concern (12).
PATHOGENESIS AND PATHOPHYSIOLOGY
The role of organic components in the pathophysiology of insomnia is well documented.
There is growing evidence that shows the biological basis of psychophysiological
insomnia to be moderate physiological hyperarousal or an imbalance of
the sleep–wake system toward alertness. Physiological hyperarousal is documented
in many other types of primary insomnia as well (14,15).