Download Errors in the recognition and diagnosis of sleep disorders

Latest Advances in Psychiatry
Misinterpretation of sleep disorders
Errors in the recognition and
diagnosis of sleep disorders
The lecture‘Sleep Disorders – an Update for Psychiatrists’ was given by Professor Gregory
Stores at the eighth Latest Advances in Psychiatry Symposium in London in March.
Professor Stores discussed the fact that sleep disorders can often be misinterpreted as
psychiatric disorders, and in this article, he provides more information on this
often-neglected topic.
T
Gregory Stores
MD, MA, DPM,
FRCPsych, FRCP
There are many impor tant connections between sleep disorders
and psychiatry, as follows:
• Sleep disturbance commonly
causes psychological problems
resulting from ef fects on emotional state and behaviour, cognitive function and performance at
work or at school, family and
social life, and quality of life in
general.1 Severe, sustained sleep
loss can even induce psychotic
phenomena.
• Disturbed sleep (often to a
severe extent) is a common feature
of psychiatric disorders in all ages.2
• Sleep disturbance, including circadian sleep-wake rhythm disturbance, can have a profound effect
on the pattern and course of psychiatric disorders,3 and insomnia
or hypersomnia can be the harbinger of the onset or recurrence of
psychiatric disorders.4
• Unwanted effects of certain psychiatric medications include sleep
disturbance, which can be severe.
Examples include insomnia
caused by some SSRIs, and excessive sleepiness produced by sedating tricyclic drugs. Withdrawal
from sedative-hypnotic substances can cause ‘rebound
insomnia’. Detailed reviews of
psychotropic dr ugs (and other
medications) that induce insomnia or sleepiness have been published recently.5,6
Some psychotropic drugs may
also precipitate parasomnias.
Certain antidepressants, lithium
and zolpidem, as well as other
CNS-depressant medication, have
been reported to precipitate sleepwalking episodes or nightmares,7
and antidepressants may also
increase periodic limb movements in sleep, decreasing its
restorative value.
An acute form of rapid eye
movement (REM) sleep behaviour disorder (RBD; see later) has
been associated with intoxication
with antidepressants and withdrawal from sedative-hypnotic
abuse as well as alcohol.8
• Sleep disorders can be misinterpreted as psychiatric conditions.
This last connection is the
main subject of this ar ticle. It is
chosen because it is not often considered in the literature despite its
basic importance both in clinical
practice and in psychiatric
research.
Sleep disorders in neurology
and general medicine
First, however, is also appropriate
to mention connections with clinical practice in neurology and
other medical specialties in order
to demonstrate the widespread
relevance of sleep disorders and
the importance of this for liaison
psychiatric ser vices.
24 Progress in Neurology and Psychiatry
• Most medical disorders in
adults and children are complicated by sleep disturbance.
• Some sleep disorders are essentially medical in type, eg obstructive sleep apnoea (OSA),
nocturnal epilepsy, and some
cases of RBD, which can foretell
the emergence of neurodegenerative disorders.
• Certain sleep disorders predispose to medical conditions. Night
shift work disorder is linked with
peptic ulcer, ischaemic heart disease and pregnancy problems. 1
OSA can lead to hyper tension
and stroke and can exacerbate
epilepsy.
• Some general medical dr ugs
(for example those used in respirator y disease, cardiac disease,
hypertension or Parkinson’s disease) are reported to cause sleep
loss or disruption.5,6 Parasomnias
may be triggered by beta-blockers
and antiparkinsonian agents
(nightmares) 7 or by treatments
for neurodegenerative disease
(RBD).8
Causes and consequences of
misinterpretation
The subject of sleep and its disorders is seriously neglected. As
long ago as the 16th centur y,
Thomas Phaire, in the first
English textbook of paediatrics,
emphasised the basic biological
importance of sleep by equating it
to the need for food: ‘Slepe is the
nouyshment and food of a sucking
child, and asmuch requisite as ye
ver y teate, wherefore wha it is
depriued of the naturall rest, all the
hole body falleth in disteper...’.9
Despite this early assertion, it
is only in comparatively recent
times that sleep and its disorders
has become the subject of any systematic, scientific enquiry. In fact,
much is now established but little
of this knowledge has found its
way into public health education
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Latest Advances in Psychiatry
Misinterpretation of sleep disorders
and the teaching and training of
health professionals and others
professionals to whose work such
knowledge is relevant.
The consequences of this continuing widespread educational
shor tcoming, now increasingly
recognised as a public health
problem 1 but at a slow pace,
include the following:
• The general public often fail to
see sleep disturbance as requiring
professional advice. For example,
only a minority of those with such
a serious sleep disorders as OSA
seek medical attention. Commonly,
parents (especially those with children with neurodevelopmental disorders) think that sleep problems
are inevitable and cannot be prevented or treated, which is not the
case. As discussed later, parents
may well interpret the consequences of par tly biologicallybased sleep disturbance in
teenagers as ‘typical adolescent
waywardness’.10
• Teachers and educational psychologists encounter the school
problems of some children and
adolescents without necessarily
realising that they are caused by
the common problem (especially
in adolescence) of inadequate
sleep.11
• Both GPs and specialist physicians, including psychiatrists, also
might be unaware of the extent to
which symptoms of sleep disorders can overlap with those of
other conditions with the
inevitable risk of, at least, diagnostic uncertainty.
Examples of misinterpretation
There are just three basic sleep
problems or complaints. These
are insomnia, excessive daytime
sleepiness and parasomnias, ie
unusual behaviours or experiences occurring on going to
sleep, during sleep or when waking up.
However, there are nearly 100
officially recognised sleep disorders that are the possible underlying cause of an individual’s sleep
problem.12 Collectively, such disorders are ver y common in all
sections of the population. As
appropriate advice and treatment
depends on the cause of a sleep
problem, it is essential to identify
the sleep disorder in each case.
In the following sections, following some points about misinterpretation of sleep disorders in general,
specific examples are given concerning the possible causes of the
three sleep problems.
Sleep disorders underlying insomnia
Persistently not being able to
sleep well (including not being
refreshed by sleep) is likely to
cause tiredness, fatigue, irritability, poor concentration, depression or impaired per formance,
perhaps leading to injuries or accidents at work or while driving. Of
the various possible explanations
for such changes, sleep disturbance may well be overlooked
with failure to appreciate that,
with an improvement in sleep
(which is usually possible with
the correct advice), such problems will often be resolved.
Occupational groups at special
risk of sleep disturbance and
its harmful effects include some
clinicians.13
The features of individual sleep
disorders in this insomnia categor y are open to misinterpretations of a more specific nature. The
following are examples of this:
• Delayed sleep phase syndrome
(DSPS) 14 Dif ficulty getting to
sleep until very late and problems
getting up in the morning, as well
as daytime sleepiness and sleeping in late at weekend, characterise DSPS. These features are
easily misinterpreted as awkward,
lazy or irresponsible behaviour, or
26 Progress in Neurology and Psychiatry
the usual form of school refusal,
especially in adolescents in whom
DSPS is common. In teenagers, it
is the result of a combination of
normal pubertal biological body
clock changes, which shift the
sleep phase later, and alterations
in lifestyle involving staying up
late for study or social reasons.
The risk that the fundamental
cause of the problem will not be
recognised is increased if alcohol
or hypnotic drugs are taken in an
attempt to get to sleep, or stimulants taken to tr y to stay awake
during the day.
• Advanced sleep phase syndrome
(ASPS)15 Because of body clock
changes occurring in old age,
there is a tendency to fall asleep
in the evening (ASPS, opposite to
the effect of body clock changes
at puber ty). The early morning
waking when sleep requirements
have been met should not be mistaken for the early morning waking associated with depression
where the total amount of sleep is
reduced.
• Jet lag 16 is another circadian
rhythm sleep-wake cycle disorder,
which, like DSPS, causes both
insomnia and excessive daytime
sleepiness. These effects are usually short-lived, but travellers who
frequently cross several time
zones on each flight can develop
chronic sleep disturbances with
serious effects on mood, performance and physical well-being, the
true cause of which may not be
appreciated.
Excessive daytime sleepiness
Excessive sleepiness, whatever its
cause, out of the many possibilities, is often misjudged as laziness,
loss of interest, daydreaming, lack
of motivation, depression, intellectual failure or other unwelcome
states of mind. Sometimes, in very
sleepy states, periods of ‘automatic’ behaviour occur, ie prowww.progressnp.com
Latest Advances in Psychiatry
Misinterpretation of sleep disorders
longed, complex and often inappropriate behaviour with impaired
awareness of events and, therefore, amnesia for them. Such
episodes can easily be misconstrued as reprehensible or dissociative behaviour, or prolonged
seizure states. The paradoxical
effect in young children of sleepiness causing overactivity has
sometimes led to a diagnosis of
attention deficit hyperactivity disorder (ADHD), inappropriately
treated with stimulant dr ugs
instead of treatment for the sleep
disorder.17
The following sleep disorders
provide examples of the general
tendency to misconstr ue the
cause of excessive sleepiness:
• Shift work disorder 18 Over 20
per cent of employees work shifts.
Night shift workers, in particular,
suffer from inadequate and poor
quality sleep because they are
required to work when their body
clock is telling them that they
should be asleep. Their daytime
sleep is usually shor ter and of
poorer quality than that previously obtained at night. This shift
work disorder is associated with
various forms of physical ill
health. The psychological effects
of inadequate or poor quality
sleep, compounded by the disruptive influence of shift work on
family and social life, are commonplace in shift workers.1
These physical health issues
and unfortunate psychosocial consequences can easily overshadow
and distract from the true origins
of the shift worker’s primary problems and lead to referral exclusively to medical or psychiatric
services without advice about the
underlying sleep disorder.
• OSA, 19 which af fects about 4
per cent of men, at least 2 per cent
of women, and perhaps 2 per cent
of children, can cause excessive
sleepiness, changes of personality
and adverse effects on social life
and performance at work, as well
as intellectual deterioration to the
extent that sometimes dementia
is suspected. Only about a tenth
of adults with OSA seek medical
advice, probably because many
others do not realise that their
daytime problems are the result
of their disr upted sleep. Those
who have sought medical advice
may well have been treated initially, before their sleep disorder
was recognised, for the complications of their OSA (such as hypertension or depression) rather than
the OSA itself. 20 Clearly, early
recognition of this treatable condition is highly desirable.
The same is tr ue of OSA in
children, the usual cause of which
at this age is enlarged tonsils and
adenoids. Their removal can
improve the child’s sleep with the
ef fect of, at least, lessening any
learning and behaviour problems
which, other wise, are likely to
have been attributed to the other,
more usual causes. OSA, usually
of more varied origins, complicates many forms of learning disability, notably Down syndrome.21
• Narcolepsy, 22 characterised
mainly by sleep attacks, as well as
more general sleepiness, is not
the rarity once supposed. Its
prevalence in western societies is
in the order of 0.02-0.05 per cent,
which is only somewhat less than
Parkinson’s disease or multiple
sclerosis. Cataplexy, with recurrent loss of tone causing collapse
or weakness of one par t of the
body or another, usually in
response to strong emotion, is
usually also present. This offers
even more scope for mistakes as
it can be misconstr ued as syncope, epilepsy or attention-seeking behaviour. Other possible
components of the narcolepsy
syndrome (namely, hallucinations, which can be especially
28 Progress in Neurology and Psychiatry
vivid, and sleep paralysis, as well
as associated automatic behaviour) are also open to misinterpretation.
It has been repor ted that, in
the year prior to the diagnosis
being definitively made at a sleep
disorders centre, narcolepsy had
been considered in only 38 per
cent of cases. 23 Incorrect diagnoses had included other neurological disorders such as epilepsy
and a variety of psychiatric problems, especially neurosis and
depression. Neurologists had
made the correct diagnosis in 55
per cent of the cases they had
seen, internists in 23.5 per cent,
GPs in 21.9 per cent and
psychiatrists in 11 per cent.
Paediatricians had failed to recognise the condition as narcolepsy
in all the children they had seen,
possibly because of the special difficulties that can be encountered
in recognising the condition at an
early age,24 but also because it is
not usually realised that the onset
of narcolepsy occurs before adulthood in at least a third of cases.
Hypothyroidism and hypoglycaemia are other possible misdiagnoses of narcolepsy.
• Kleine-Levin syndrome 25 The
episodic, prolonged sleepiness in
the Kleine-Levin syndrome,
accompanied by often bizarre and
out of character behaviour when
the patient is awake, understandably causes confusion in the
minds of those who are unfamiliar
with the condition. Some people
with this disorder have initially
been thought to perhaps have
encephalitis, a cerebral tumour,
epilepsy, drug addiction or a psychiatric problem including conduct disorder.26
Parasomnias
As it is not generally realised how
complicated behaviour can be
during sleep, the many different
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Misinterpretation of sleep disorders
types of parasomnias are perhaps
at par ticular risk of being confused with other conditions and
also with each other.
• Sleepwalking and sleep terrors7
The common, inherited conditions of sleepwalking and the
related ‘partial arousal disorders’
(sleep terrors and confusional
arousals) occur during non-rapid
eye movement (NREM) sleep,
mainly early in the night. While
sleepwalking may involve calm
walking about in a semi-purposeful confused manner, some sleepwalkers do much more complex
things such as making themselves
drinks or meals, following complicated routes outside the house, or
even driving a car.
People with agitated sleepwalking or sleep terrors appear to
be very fearful and distressed and
rush about and cry out as if escaping from danger. Other sleepwalkers develop an eating disorder
with excessive weight gain due to
the amount of food they consume
while they are still asleep at night.
Yet others behave in an aggressive or destructive way causing
injury to themselves or other people. At times, sexual or other
serious offences have been committed during a sleepwalking
episode (and, indeed, some other
sleep disorders). The young children who have confusional
arousals may well be thought by
their parents to be ill in some way
because of the degree of behavioural disturbance involved, which
is similar to that of sleep terrors.
If it is not known that such
complicated actions are compatible with still being asleep, it is
likely to be assumed that the person was awake at the time and
aware of what he or she was
doing, and, therefore, responsible
for
what
has
happened.
Alternatively, the episodes might
be thought to be epileptic in
nature, or the result of some other
physical or psychiatric state.
Guidelines have been suggested
for the recognition of sleepwalking automatisms, mainly for
medico-legal purposes.27
• ‘Isolated’ sleep paralysis, 28 ie
other than that associated with
narcolepsy, which occurs briefly
when going to sleep or on waking
up, is not uncommon but often
unreported unless it is frequent.
Although benign, it can generate
much anxiety and fear of having
a stroke or other neurological
problem.
• Sleep-related hallucinations 29
(‘hypnagogic’ when falling asleep;
‘hypnopompic’ when waking up),
involving various sensory modalities, are also common and can be
frightening, especially to children.
When combined with sleep paralysis, the experience can be so
complicated and bizarre (including conversations with people or
other beings, as well as feelings of
threat and dread) that a psychotic
process, especially of a schizophrenic nature, may well be suspected.30
• Rhythmic movement disorder31
Parents of the many young children who bang their heads or roll
about rhythmically at night may
worry that this is a sign of an emotional problem or neurological disorder, par ticularly epilepsy. In
fact, rhythmic movement disorder
is also benign and usually remits
spontaneously by the age of three
to four years, although occasionally it persists into adult life.
• Nocturnal frontal lobe epilepsy
(NFLE)32 A number of non-convulsive types of epilepsy are
closely related to sleep including
NFLE. These, like REM sleep
behaviour disorder, are ‘secondary parasomnias’ in that they are
or can be manifestations of a medical disorder. All can give rise to
dramatic behaviour that is easily
30 Progress in Neurology and Psychiatry
construed as some other type of
night-time disturbance.
This is particularly so in NFLE
because the seizures can consist
of movements such as kicking,
hitting or thrashing, and vocalisations, which include screaming
shouting and roaring. Both adults
and children with this condition
are at serious risk of being misdiagnosed as experiencing other
dramatic events such as sleep terrors or pseudoseizures (especially
because even ictal EEGs can be
unremarkable).
• Nocturnal panic attacks 33 are
another form of secondar y parasomnia, this time being part of a
psychiatric disorder. If panic
attacks occur only at night, they
might well be misdiagnosed as
some other form of dramatic parasomnia such as sleep terror or
nightmare. They are characterised by sudden awakening in a
highly aroused state with dizziness, difficulty breathing, sweating, trembling and palpitations, as
well as a fear of an impending and
possibly fatal hear t attack or
stroke.
• RBD8 In this disorder, muscle
tone is pathologically retained
during REM sleep, allowing
dreams to be acted out (most
dreaming occurs during REM
sleep). Violent dreams are likely
to cause injur y to the patient or
bed partner.
RBD has many causes or associated conditions, including a
strong association with neurodegenerative disorders such as
Lewy body disease, multiple system atrophy, Parkinson’s disease,
and also with narcolepsy. There is
also a link with some forms of
medication, including antidepressants. Although mainly described
in elderly males, it has also been
reported at other ages, including
children, and in women. The condition (which is eminently treatwww.progressnp.com
Latest Advances in Psychiatry
Misinterpretation of sleep disorders
able, mainly with clonazepam,
even in the presence of neurodegenerative disease) may well be
confused with other dramatic parasomnias despite their dif ferent,
distinctive features. Especially if
the bed partner is attacked, a psychological motive may be wrongly
suspected.
• Parasomnia overlap disorder34
A combination of sleepwalking
and night terrors, as well as RBD,
known as parasomnia overlap disorder, has been described in some
individuals.
Assessment
The risk of misdiagnosis can be
lessened by being acquainted
with the various sleep disorders
including an awareness of their
main characteristic features. A
patient may have a combination of
sleep disorder and other conditions of a dif ferent nature (and,
indeed, more than one type of
sleep disorder), especially in the
elderly. Therefore, it is all the
more impor tant that each complaint and its cause, including the
possibility of sleep disorder, are
assessed thoroughly. Assessment
needs to include a sleep histor y,
which traditionally has been neglected.35
Sleep history
The following outline illustrates
the main clinical enquiries that
should supplement usual historytaking schedules. A more detailed
account is provided elsewhere;36
a modified approach is required in
the case of children and adolescents.37
Three basic screening questions for any patient are:
• Do you have any difficulty getting off to sleep or staying asleep?
• Are you ver y sleepy during the
day?
• Do you have any disturbed
episodes at night?
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Key points
• In many ways sleep and its disorders is a fundamentally important topic in clinical
practice
• There is the risk that such disorders are mistaken for various psychiatric or other
medical conditions including those of a neurological nature.This is highly likely to result in
wrong advice and treatment
• Examples are given of how this can happen in various sleep disorders underlying the basic
sleep problems of insomnia, excessive sleepiness, and unusual behaviour associated with
sleep (parasomnias)
• Such diagnostic errors are less likely to occur with a better understanding of the sleep
disorders field (which tends to be neglected in professional training) and improved
attention to sleep patterns and behaviour seen as a routine part of the clinical assessment
of each individual case
The patient’s bed par tner or
other relative should also be questioned. Positive answers call for a
detailed sleep histor y, essential
elements of which are:
• The precise nature of the sleep
complaint, its onset and its development.
• Medical or psychological factors
at the start of the sleep problem or
which might be maintaining it.
• Patterns of occurrence of the
sleep problem including provoking or ameliorating factors, and
dif ferences in sleep patterns
between weekdays and weekends.
• The sleeping environment, regularity of sleep habits and other
aspects of ‘sleep hygiene’, ie practices that are conducive to sleep.38
• Ef fects on mood, work, social
life and other family members.
• Effects of past and present treatments for the sleep problem, and
medications taken now or in the
past for other conditions.
• Details of the patient’s typical
24-hour sleep-wake pattern, starting with evening events leading
up to bedtime, time and process
of getting to sleep, events during
the night, time and ease of waking
up, daytime sleepiness (including
naps), as well as mental state and
behaviour during the day.
• Estimation of the duration and
soundness of overnight sleep.
• Features of particular diagnostic
importance such as a combination
of obesity, loud snoring or snorting
and apnoeic episodes (OSA), wide
discrepancy between weekday and
weekend sleep patterns (DSPS),
sleep attacks and cataplexy (narcolepsy), repeated jerking at night
(periodic limb movements in
sleep), or violent dreams and
behaviour during sleep (RBD).
Other aspects of assessment
A screening questionnaire for use
with adults39 or younger patients40
can be a useful star ting point in
assessment. A str uctured sleep
diar y, recording day and night
events for one to two weeks, may
also reveal further valuable information.
Other potentially relevant
details may be contained in the
patient’s medical, psychiatric and
social histories including occupational factors and also habits
(such as caffeine, alcohol or nicotine consumption and use of illicit
drugs) that might affect sleep. A
family histor y of sleep disorders
might also be revealing.
These enquiries should be
accompanied by a review of sys-
Progress in Neurology and Psychiatry 31
Latest Advances in Psychiatry
Misinterpretation of sleep disorders
tems, as well as physical and mental state examination. It is important to identify any neurological,
general medical or psychiatric disorder likely to affect sleep, or physical anomalies of possible
importance such as those that predispose to OSA, especially obesity
and nasopharyngeal abnormalities.
Clinical information from these
sources may well be sufficient to
at least provisionally formulate the
problem correctly. In a proportion
of cases, special investigations or
referral to a sleep disorders service will be required.
Conclusions
For the reasons outlined in this
article concerning the relevance
of sleep disorders to clinical practice in psychiatr y and other specialities, professional training in
this field can be considered essential. Allied to an improved understanding by the general public (to
aid which publications are now
available)41,42 this would reduce
the risk of inappropriate advice
and treatment that inevitably follow misinterpretations of the
types described.
How often such mistakes are
actually made is not known but,
until knowledge of sleep disorders
on the part of both the public and
professionals improve, they seem
likely. The same can be said
(although probably to a lesser
extent) of psychiatric disorders
being mistaken for sleep disorders
about which even less is known,
apart from occasional case reports.
Professor Stores is Emeritus
Professor of Developmental
Neuropsychiatry at the University
of Oxford
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