EU_Psychiatry_Mignot_Capasso_quark6.qxp 30/6/08 02:22 Page 49
Diagnosis and Management of Common Sleep Disorders – An Overview for the Psychiatrist
sleep onset or upon awakening, mainly from REM sleep, despite being Current treatments for narcolepsy are aimed at specific symptoms and
mentally awake, and usually lasting just a few seconds).
41
Sleep paralysis are not directed against the disease as a whole. Treatment includes
and sleep-related hallucinations are present in only 50% of people with stimulants (modafinil, methylphenidate, amphetamines) for daytime
narcolepsy and can be present in another conditions, so cannot be used sleepiness and sleep attacks,
48–51
low-dose antidepressants (typically
in diagnosis; however, they should be carefully evaluated as occasionally venlafaxine) that are well-known for their REM suppressant capacity
patients may be misdiagnosed as schizophrenic.
42
Onset is usually during for cataplexy and other REM-associated symptoms
52,53
and hypnotics for
adolescence, although cases have been seen in those who are only a few disturbed night-time sleep. Sodium oxybate (γ-hydroxybutyrate [GHB])
years old and in those above 70 years of age. acts as a neurotransmitter via its own receptors and via the stimulation of
The negative social impact of narcolepsy has been extensively described. It
can impair driving ability, cause car or machine accidents and reduce
professional performance (leading to people becoming unemployed,
A patient with suspected narcolepsy
changing jobs frequently or retiring early).
43,44
Depression has also been
should undergo a polysomnogram
reported in 18–37% of cases.
45
A patient with suspected narcolepsy should
followed by a daytime multiple sleep
undergo a polysomnogram followed by a daytime MSLT, a test that consists
of a series of naps. It is used to see how quickly the patient falls asleep in latency test, a test that consists of a
quiet situations during the day. The MSLT is the standard way of measuring
series of naps.
the level of daytime sleepiness. The aim of the polysomnogram is to
eliminate other causes of daytime sleepiness (mainly sleep apnoea) and
to assess whether the patient has had enough sleep (at least six hours)
before the MSLT. Additionally, the polysomnogram might show a shortened GABA
B
receptors, and shows efficacy in managing REM-related
REM sleep latency. The MSLT mean daytime sleep latency is eight minutes symptoms including cataplexy, hypnagogic hallucinations and sleep
or shorter, with two or more sleep onsets in REM periods (SOREMPs). The paralysis. It is also effective against sleepiness.
54–56
Narcolepsy/hypocretin
time from sleep onset to REM sleep should be less than 15 minutes in at deficiency can be associated with schizophrenia, depression, anxiety,
least two naps. An additional diagnostic tool for the identification of obsessive compulsive disorder and any other psychiatric conditions. In
narcolepsy with cataplexy is the association with a specific human leukocyte these cases, the clinical picture is often more difficult to recognise, and
antigen (HLA) allele, the DQB1*0602, identified in 85–95% of patients with treatment is more difficult.
narcolepsy–cataplexy. However, in the US 12% of Asian people, 25% of
white people and 38% of African-Americans in the general population have Hypersomnia
this allele, but obviously only a small fraction of these have In contrast to narcolepsy–cataplexy, a disorder with a clear
narcolepsy. Additionally, HLA is positive in only 40–60% of patients pathophysiology (HLA-associated hypocretin deficiency), a number of
with narcolepsy without cataplexy, and in 75% of familial cases of patients present with sleepiness, some of the narcolepsy symptoms and/or
narcolepsy.
46,47
However, importantly, sleep paralysis and dream-like diagnostic results (positive sleep test with short REM latency and/or short
hallucinations also occur in isolation in normal people, often in association sleep latency; HLA positivity) but not low CSF hypocretin. Some of these
with sleep deprivation, anxiety and depression. patients experience severe sleepiness, excessive sleep (more than 10 hours
of daytime sleep every day) and documented abnormal MSLT. In these
Measuring CSF-hypocretin-1, obtained through lumbar puncture, is unusual cases, neurological work-up is important. More commonly,
often useful in making the diagnosis of narcolepsy. CSF hypocretin 1 patients may present with mildly abnormal nocturnal sleep (mild insomnia,
concentrations lower than 110ng/l, or 30% of local normal short sleep), excessive napping, a borderline positive MSLT (with or
values, are highly indicative of narcolepsy. Low CSF hypocretin without SOREMPs) and significant subjective complaints of daytime
fatigue and sleepiness. In these cases, it is not uncommon to have a
combination of problems, such as mild SDB, insufficient nocturnal sleep,
Narcolepsy is a serious sleep disorder
depression/anxiety and/or some element of conversion disorder. In these
characterised by excessive daytime
cases, the clinician should treat one condition after the other, using (in
order) behavioural and light therapy to consolidate nocturnal sleep, mild
sleepiness and abnormal rapid eye
non-amphetamine stimulants (atomoxetine, modafinil) to treat a possible
movement (REM) sleep manifestations,
central nervous system (CNS) hypersomnia, CPAP to treat mild sleep
apnoea and antidepressants and psychotherapy if depression or anxiety
including cataplexy sleep paralysis,
disorders are present. Stronger treatments using amphetamine stimulants
hypnagogic and hypnopompic may be needed, but are best limited, as it is not uncommon for patients
hallucinations and sleep-onset
to develop a rapid tolerance.
REM periods.
The special case of Kleine-Levin Syndrome (KLS), which is probably less
rare than commonly thought, should be mentioned, as it is commonly
concentrations are highly specific (99%) and sensitive (87–89%) for misdiagnosed as a psychiatric condition. The disorder affects
patients with clear-cut cataplexy, and specific (99%) but not sensitive adolescents (often males) and is characterised by dramatic and sudden
(16%) for those with mild, atypical or absent cataplexy, and for episodes of sleepiness (sleeping for more than 14 hours per day) with a
patients with familial or HLA-negative narcolepsy.
37,42
general feeling of fogginess and confusion. Episodes are self-limiting in
EUROPEAN PSYCHIATRIC REVIEW 49
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