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Sleep and Mental Disorders
Last edited |
10/30/2008
Written by Maurice M. Ohayon, MD, DSc, PhD
Sleep disorders and psychiatric disorders are
closely interrelated: Sleep disorders are rarely without some degrees of mood
disturbances and psychiatric disorders are often accompanied with sleep
disturbances
Hence, sleep disorders associated with a
psychiatric pathology can be primary or secondary. The distinction between these
two possibilities bear important issues both for prognostic and treatment.
The American Classification of Mental Disorders (DSM-IV) provides some
guidelines to distinguish between primary and secondary sleep disorders:
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A sleep
disorder is judged to be primary in nature when no etiology can be identified or
when, related to a mental disorder, it is sufficiently severe to warrant
independent clinical attention.
Such patients focus on their sleep disturbances
and sublimate their psychiatric symptomatology (which may emerge only after a
systematic questioning).
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Epidemiological studies exploring the complexity of relationships between sleep
and mental disorders are scarce but provide some indications about the magnitude
of the phenomenon. These data help in our understanding of the problem and
impact on the treatment and the follow-up of patients.
Traditionally, international classifications
distinguish three main categories of sleep disorders associated with Mental
Disorders:
Mental Disorders producing Insomnia
Depression
In the general population, between
35% to 75% of
depressed individuals complain of insomnia.
(Higher figures pertain in psychiatric clinics).
These complaints are mainly difficulties of initiating or maintaining sleep
(disrupted sleep and early morning awakenings).
The insomnia complaints in depressed individuals result in a diagnosis of
Insomnia related to a mental disorder in about 10% of cases in the general
population (1-3). In sleep disorders clinics, this figure is higher with rates
of typically 20% or over.
Many clinical studies have shown polysomnographic abnormalities in sleep
during a major depressive episode. The precocious appearance of paradoxical
sleep is the most widely recognized phenomenon. This shortening is observed in
two-third of the cases.
Mania
Insomnia is also considered a
precocious symptom of a manic episode.
In the general population, near 70% of individuals having experienced a manic
episode reported insomnia complaints, mainly a disrupted sleep.
These insomnia complaints will lead to a diagnosis of Insomnia related to
another mental disorder in about 15% of cases. Polysomnographic studies with
manic patients are scarce. The main findings of these studies shown reduced
total sleep time and sleep efficacy.
Anxiety
disordersInsomnia
complaints are present at different levels in most of individuals with
anxiety disorders.
Indeed, close 80% of individuals with an anxiety disorder complain of insomnia
in the general population.
About half of them reported a disrupted sleep or difficulties in initiating
sleep.
Some polysomnographic studies have been done with patients having a
Generalized Anxiety Disorder, a Panic Disorder, or a Posttraumatic Stress
Disorder.
Generally speaking,
the REM sleep of anxious patients is not disturbed as in the case of major
depressive episodes. However, sleep latency is increased as compared to
non-insomnia subjects and total sleep time as well as sleep efficiency are
reduced.
Some nocturnal panic
attacks have been recorded: the interest of these recordings is that they show
that these attacks mainly occur between stages 2 and 3 as opposed to during
nightmares (REM sleep) or night terrors (stage 4).
Psychotic disorders
Most of schizophrenic
patients complain of a poor sleep.
However, there are few
studies in schizophrenic patients not taking drugs on which to base any
description of sleep changes.
Clinical studies
indicate that there is a decline in sleep efficiency; the sleep is disrupted and
there is a decline in the REM latency as observed also in major depressive
episodes.
Anorexic patients Anorexic patients have a diminution of
total sleep time and an increase in the amount of time awake at night.
Generally speaking, these changes are related to the severity of weight lost
and the symptoms improve when there is a weight gain although there may be a
lag phase and/or a period of hypersomnolence after the reoccurrence of
puberty.
Personality disorders
would be also present in about 26% of patients complaining of insomnia.
Mental Disorders producing hypersomnia
Hypersomnia and
excessive daytime sleepiness are not synonymous but the two concepts are
frequently confused:
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hypersomnia is defined as
an extended amount of sleep or as getting too much sleep compared to individuals
in the same age group. It is a rare phenomenon involving less than 1% of the
general population.
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Excessive daytime sleepiness refers to a need
for sleeping in inappropriate situations, for example at work.
The consequences of excessive daytime
sleepiness can be extremely serious: about one fourth of road accidents, one
half of work-related accidents and one quarter of household accidents are caused
by sleepiness.
Depression
Hypersomnia affects
about 2% of depressed individuals in the general population while excessive
daytime sleepiness is reported by about 40% of them (4). In clinical studies,
between 10% to 75% of depressive patients complaints of hypersomnia.
Excessive
daytime sleepiness could be a consequence of insomnia in about 40% of
depressed individuals and 25% of those with a bipolar disorder.
Few polysomnographic studies have been performed with patients having a mood
disorder in relationship to hypersomnia or excessive daytime sleepiness.
Multiple Sleep Latency Tests (MSLT) did not reveal abnormalities in the
daytime sleep latency. Excessive daytime sleepiness in mood disorders appears
to be more subjective in nature.
Anxiety disordersHypersomnia or excessive daytime sleepiness in individuals with an
anxiety disorder have received little attention in clinical studies.
In the
general population, hypersomnia is described by 1.6% of individuals with
anxiety disorders and excessive daytime sleepiness in about 30% of them (4).
Generally speaking,
excessive daytime sleepiness is more frequently severe in depressed individuals
while it is mainly moderate in individuals with anxiety disorders.
Mania
Hypersomnia is rarely reported by individuals having experienced a manic
episode (less than 1%). Excessive daytime sleepiness is more frequent
affecting about one third of individuals.
Psychotic disorders
In general, the
separation of sleepiness and tiredness or fatigue is poorly tackled by
physicians and by tests.
In many schizophrenic
patients, the process of withdrawal and apathy combined with leading questions
about sleep change leads to reported changes in sleep which may be overstated.
Mental Disorders producing
Parasomnias
Parasomnias are a heterogeneous group of sleep disorders that
are not strictly speaking abnormalities or dysfunctions of the processes
underlying sleep-wake states.
Most of these disorders are relatively frequent and benign in children and
adolescents and disappear in early adulthood.
The presence of some of these disorders in adults, such as nightmares, night
terrors or confusional arousals may be indicative of a more severe disorder.
Adults with night terrors exhibit a high level of anxiety, depression,
obsessive-compulsive and phobic traits on personality questionnaires such as the
MMPI.
Furthermore, mental stress and specific life events have been reported to
trigger or increase the frequency of night terror and sleepwalking episodes.
Nightmares
Nightmares in adults are associated with various
psychiatric disorders (6).
Continuous recurrent nightmares positively response to antidepressant
medications in depressed individuals.
Nightmares are also frequently observed in
schizophrenic patients and acute schizophrenic episodes are often
preceded of a period of frequent nightmares.
Individuals with a posttraumatic stress disorder
may also experience recurrent nightmares about the traumatic event.
Eating Abnormalities
The common association of sleep and eating
abnormalities in patients with former sexual abuse (and other
traumas) leads to many misdiagnoses in general practice (and in specialist sleep
clinics).
Violent Behaviors Violent behaviors during sleep are not so rare: 2% of the
British public have experienced such behaviors (7). These individuals present
more frequently anxiety and mood disorders
(20% to 25%).
Sleep
Paralysis Sleep paralysis is a transient and generalized inability
to move and speak that occur during the transitional period between sleep and
wakefulness. Episodes vary from one to several minutes and are usually extremely
distressing especially when they are accompanied with
hypnagogic or hypnopompic hallucinations.
Sleep paralysis occurs in 30 to 60% of
narcoleptic
patients. Epidemiological studies shown that 6.2% of the general population
experienced at least one such episode in their lifetime. Moreover, sleep
paralysis is often associated with a mental disorder. In some cases, anxiolytic
medication may be responsible for this manifestation (8).
References
1. Ohayon MM. Prevalence of DSM-IV diagnostic criteria
of insomnia: distinguishing insomnia related to mental disorders from sleep
disorders. J Psychiatr Res 1997; 31: 333-46.
2. Ohayon MM, Caulet M, Lemoine P. Comorbidity of mental and insomnia
disorders in the general population. Compr Psychiatry 1998;39:185-197.
3. Ohayon MM, Caulet M, Priest RG, Guilleminault C. DSM-IV and ICSD-90
insomnia symptoms and sleep dissatisfaction. Br J Psychiatry
1997;171:382-88.
4. Ohayon MM, Caulet M, Philip P, Guilleminault C, Priest RG. How sleep and
mental disorders are related to complaints of daytime sleepiness. Arch
Intern Med 1997;157:2645-52.
6. Ohayon MM, Morselli PL, Guilleminault C. Prevalence of nightmares and its
relationship to psychopathology and daytime functioning in insomnia subjects.
Sleep 1997; 20:340-8.
7. Ohayon MM, Caulet M, Priest RG. Violent behaviour during sleep. J Clin
Psychiatry 1997;58:369-76.
8. Ohayon MM, Zulley J, Guilleminault C, Smirne S. Prevalence and
pathological associations of sleep paralysis in the general population.
Neurology 1999; 52: 1194-200.
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