Sleep and psychiatric disorders often occur at the same time,
and untreated sleep disorders can increase the risk of developing
psychiatric conditions, such as depression, later in life. Recent
reports found that as many as two-thirds of patients referred to
sleep disorders centers have a psychiatric disorder. The most
common psychiatric disorders associated with sleep complaints
include depression, anxiety, and substance (illicit drugs and
alcohol) abuse. Treating sleep disorders has been shown to improve
the co-existing psychiatric condition and overall quality of life.
Depression
Depression is a mood disorder identified by low mood and/or lack of
interest in activities previously found to be enjoyable. Depression
affects one's appetite, concentration, energy level, and
motivation. People with depression report feelings of helplessness,
hopelessness, worthlessness, and have suicidal thoughts. The
majority experience symptoms of insomnia, consisting of difficulty
in falling asleep, staying asleep, early morning awakening, or
non-refreshing sleep.
Studies of depressed patients demonstrate prolonged sleep
latency (time to fall asleep), lack of slow wave sleep (also known
as deep sleep), reduced REM sleep latency (time to REM sleep from
sleep onset), and increased amount of REM sleep. REM stands for
rapid eye movement, a sleep cycle characterized by the following
physiological changes:
- Accelerated respiration
- Increased brain activity
- Eye movement
- Muscle relaxation
There is much evidence linking depression with sleep disorders.
It has been shown that insomnia increases the risk of depression
and that depression can cause insomnia. In a 34-year follow-up
study of medical students at Johns Hopkins Medical Center, the risk
of developing depression among students with insomnia was twice
that of those without insomnia. Of all the symptoms of depression,
insomnia is often the last to respond to medications. Failure to
treat insomnia increases the risk of a depression relapse.
Rarely, people with depression report excessive daytime
sleepiness. This is more common in patients with seasonal affective
disorder, also known as "winter depression."
Anxiety disorders
People with anxiety disorders feel nervous, tense, have difficulty
controlling worrying, and find it hard to relax. Sleep disorders
are found in over 50 percent of patients with generalized anxiety
disorder. Difficulty in falling and staying asleep is the most
common sleep disturbance. People with anxiety disorders report a
high level of psychological distress and are unable to relax enough
to sleep at night. Insomnia in turn can raise anxiety levels.
Nocturnal panic attacks are also common; these are sudden
awakenings from sleep accompanied by intense anxiety, shortness of
breath, heart palpitations, and usually lead to difficulty falling
back asleep.