Psychopharmacology: Learning Disability

A. Asperger’s syndrome

This pattern is typical of Asperger’s syndrome (A), a condition which is
still not fully understood, but shares similarities with autism in terms
of qualitative abnormalities in social interactions as well as unusual or
intense interest in a restricted range of behaviours or activities. Motor
clumsiness is also common. Unlike autism (C), however, there is usually
no language delay or marked cognitive difficulties, which are the other
hallmarks of that disorder. The disorder usually persists into adolescence
and adulthood and there is also an association with psychotic episodes.
While the lack of warmth may lead one to think of an attachment
disorder (B), the other symptoms would not be typical for such a
diagnosis. Attachment disorders are considered elsewhere in this book.
This history would not suggest a conduct disorder (D), in which there
would typically be marked repetitive and resistant defiant or dissocial
behaviours. Conduct disorders are also considered elsewhere in this book.
There is nothing in the history to suggest Down’s syndrome (E), in which
there is usually severe development and language delay as well as a
characteristic physical appearance and associated medical problems.

C. Conduct disorder

This history strongly suggests a conduct disorder (C). These disorders have
caused significant debate as to their aetiology, with many considering
them to be a social rather than psychiatric problem. Regardless, they
cause significant problems to society as well as the individual, and
unless managed well, will almost inevitably lead to other problems in
later life. There is a strong association with adult dissocial personality
disorder (psychopathy). There are thought to be genetic, family and wider
environmental factors involved in the aetiology of these disorders. This
history is not typical of ADHD (A), in which the predominant symptoms
are those of inattention or poor concentration, hyperactivity and
fidgeting and impulsivity. While children with ADHD can be difficult to
manage, there is not such a degree of violent and destructive behaviour
as exhibited here. However, ADHD and conduct disorder are often
co-morbid with each other. Childhood disintegrative disorder (B) is a
type of pervasive developmental disorder sharing some characteristics
with childhood autism. However, unlike autism, children usually have an
initial period of entirely normal development, before a period of definite
loss of previously acquired skills and social withdrawal. Perhaps the most
difficult distractor here is ODD (D).

E. Risperidone

Risperidone (E) is an antipsychotic. These drugs should be used with
extreme caution in children, and should really only be prescribed to target
psychotic symptoms. They have the potential to cause significant harm
if not monitored carefully, and they seem to lead to more severe side
effects, such as extrapyramidal symptoms, than in adults. While there is
some evidence of antipsychotics being effective in reducing aggression
in conduct disorder, they would certainly not be a first line choice of
treatment. CBT (A) has been used effectively in conduct disorder. There
are a number of different approaches used that could be classed under
the umbrella of CBT, such as problem-solving skills training. The goal of
such therapies is for the child to develop alternative skills to approach
situations that previously had resulted in aggressive or violent behaviour.
Family therapy (B) is used in conduct disorder and will be particularly
useful in cases where there are disordered family dynamics or difficulties
in bonding and attachment within the family unit. Supporters of family
therapy believe it is helpful in avoiding excessive blame being placed
on the child for their behaviour. Methylphenidate (C) is a stimulant
medication that has been successfully used as part of the management
of conduct disorder. It is particularly effective when there is a co-morbid
element of ADHD in the presentation. Note that medications should be
combined with other forms of social and psychological therapy in the
treatment of conduct disorder. Parent management training (D) is another
effective treatment which is supported by the National Institute for
Health and Clinical Excellence. It involves parents and therapists working
together to develop specific and systematic strategies to cope with and
change aggressive behaviours.

A. Aggression towards peers

Aggression (A) is not part of the diagnostic criteria for typical ADHD,
although ADHD and conduct disorder are often co-morbid together.
If aggression is significant in the presentation, then a diagnosis of
conduct disorder should be considered. Excessive motor activity is one
of the hallmarks of ADHD (B), including fidgeting, running or climbing
excessively, leaving seats in class etc. Inattention (C) is the other major
symptom cluster in ADHD, which may manifest in numerous ways such
as appearing not to listen, making careless errors, not finishing tasks,
forgetfulness etc. Symptoms must occur in more than one setting (D),
e.g. school and home, for the diagnosis to be made. Symptoms must also
be present for at least 6 months (E) for a diagnosis to be made according
to ICD-10.

C. Enuresis

Enuresis (C) refers to involuntary voiding of urine either at night
(nocturnal enuresis) or during the day (diurnal enuresis) or both. It may
be primary, in which case the child has never achieved a period of being
dry, or secondary (as in this case), when wetting begins after a period
of being dry (usually given as at least 6 months). The latter is more
commonly associated with psychological or emotional problems, while
broadly speaking the former is often down to a developmental delay, a
structural problem or other medical causes. Cluttering (A) is the symptom
of rapid speech with a breakdown in fluency but no repetitions or
hesitations (as compared to stammering). Encopresis (B) is the voluntary
or involuntary voiding of faeces in inappropriate settings. It, like enuresis,
may be the result of a wider emotional disorder, or may be secondary
to the abnormal continuation of normal infantile incontinence. Pica (D)
refers to the persistent eating of non-nutritive substances, e.g. sand, paint,
or even faeces. Trichotillomania (E) is the specific disorder of pulling out
one’s own hair and is considered to be an impulse control disorder, with
possibly some relationship to obsessive–compulsive disorder.

B. Gilles de la Tourette syndrome

Gilles de la Tourette syndrome (B) is a chronic tic disorder in which
both vocal and motor tics are present (as in this case). The onset is
usually at around 7–10 years and tends to worsen through adolescence.
The cause is not fully understood, but there are undoubtedly both
genetic and environmental factors involved. Neuropathologically, there
are thought to be dysfunctions in thalamic, basal ganglia and frontal
cortical structures. Asperger’s syndrome (A) is a developmental disorder
predominantly associated with problems in social interaction, of which
there is no mention in the above vignette. Hyperkinetic disorder (C) refers
to a spectrum of disorders which includes ADHD. The core features of
ADHD include excessive motor activity and restlessness. Lesch–Nyhan
syndrome (D) is a rare X-linked recessive disorder that results in the
inability to metabolize uric acid, leading to hyperuricaemia. There are
numerous manifestations, including learning disability, striking selfinjurious
behaviour and odd movements that may resemble Huntington’s
chorea but equally may look like Tourette’s. However, as there is no history
given of developmental problems this would rule out this diagnosis here.

D. Psychoeducation

Psychoeducation (D) for both the patient and their carers is critical
in managing tic disorders, including Tourette’s. The purpose is to
explain the nature and course of the disorder to prevent deterioration
in personal and family functioning. People with Tourette’s are at high
risk of co-morbid disorders such as depression and obsessive–compulsive
disorder – screening for these is also critical and targeted therapy should
be recommended if they coexist. Atomoxetine (A) is a stimulant usually
used in ADHD. It has been successfully used for Tourette’s syndrome
but is probably only useful when there is co-morbid ADHD. Deep brain
stimulation (B), is still a relatively experimental technique although it
has been used for many years now. It involves the surgical implantation
of a ‘brain pacemaker’ and has been used, with mixed success, in
various movement disorders such as Parkinson’s disease, and possibly
affective disorders such as treatment-resistant depression. However, it is
still highly experimental and there is an obvious risk of complications,
and it would certainly never be used in a relatively straightforward
case of Tourette’s, and certainly not in a child. Psychoanalysis would
not be indicated here (C) and there is no evidence that it is of use in
tic disorders. Risperidone (E) is an atypical antipsychotic that has been
used successfully in Tourette’s syndrome. However, while this may be an
option, there is nothing to suggest here that the disorder is of sufficient
severity to warrant the use of antipsychotic medication in such a young
patient. It would almost certainly be best in this case to try supportive and
educational techniques in the first instance before trialling medication.

A. Epilepsy is over-represented in patients with learning disability

People with learning disability, of whatever severity, are more likely
to have co-morbid epilepsy (A), with some specific syndromes being
noticeable, such as Lennox–Gestaut syndrome and autistic spectrum
disorders. Mild learning disability is usually classified as occurring in
people with an IQ of between 50 and 70 (B). Moderate learning disability
is classified in the IQ range of 35 to 49, with severe learning disability
at 34 and below. Obviously this classification is extremely arbitrary and
the assessment and management of individuals requires much more
sophisticated tools. Schizophrenia (C), like epilepsy, is over-represented
in learning disability. Suicide is actually less common in people with
moderate and severe learning disabilities (D), although the rates for those
with mild learning disability have not been adequately established. Lack
of means may play a part in this, as may poor understanding of lethality

D. Guillain–Barré syndrome

Guillain–Barré syndrome is an ascending peripheral polyneuropathy
caused by an immune response to certain foreign antigens, the most
common being Campylobacter jejuni. There is no association with learning
disability (D). Angelman’s syndrome (A) results from inactivation of the
maternally inherited chromosome 15 (also known as genomic imprinting).
It results in severe learning disability, almost no use of language, ataxia
and unusual behaviour such as frequent laughter and highly excitable
behaviour. Down’s syndrome, or trisomy 21 (B), is an extremely common
form of learning disability. Edwards’ syndrome results from trisomy
18 (C). Only 5–10 per cent of infants will live beyond their first year.
In those that do, severe learning disability will be ubiquitous. Hunter’s
syndrome (E) is a lysosomal storage disease caused by a deficiency in the
enzyme iduronate-2-sulfatase. Despite a wide phenotypic presentation, it
is always progressive and severe. Learning disability is often, although
not always, present.

A. Alzheimer’s disease is more common in people with Down’s syndrome
than the general population

Alzheimer’s disease is over-represented in patients with Down’s syndrome
(A), and for those that survive to their sixth decade, at least 50 per
cent of people will show clinical evidence of dementia. The reason for
this is almost certainly that the amyloid precursor protein is encoded
on chromosome 21, but other genes may also be important, such as
superoxidase dismutase. Mosaicism, as opposed to nondisjunction in
gametes causing trisomy 21, occurs for only 1–2 per cent of cases of
Down’s syndrome (B). While there is some variation in the clinical
presentation of Down’s syndrome, such as only around half presenting
with congenital cardiac difficulties, all people with trisomy 21 will have
some degree of learning disability (C). While many people with Down’s
syndrome will require significant support, often including residential
placement depending on the degree of disability, many people with
trisomy 21 will be able to live independently, although will nearly always
require some support to do this (D). People with Down’s syndrome are at a
higher risk of most psychiatric disorders, including anxiety problems (E).