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).