Psychiatric Illness and Learning Disability
: Dual Diagnosis
The
North American
concept of dual diagnosis is now becoming popular in the United Kingdom to
describe those people who have a psychiatric illness in addition to a
developmental learning disability. In addition, such a person may or may not
have a mental impairment under the terms of the 1983 Mental Health Act, and/or
they may present with behaviour which is described as challenging.
Definitions
LeaningDisability,
Mental Handicap,Mental Retardation/Mental Deficiency
ICD 10
multiaxial
(I)Demographic data
(II) Cognitive level
(Ill)Physical
illness eg, Down's Syndrome
(IV) Psychiatric illness
(V)Level
of adaptive function
To qualify as having a mental handicap an
individual must have "a condition of arrested or incomplete development of
mind which is especially characterised by subnormality of intelligence and
social functioning." The assessment should be "based on whatever
information is available including clinical evidence, adaptive behaviour and
psychometric findings.
b) American Association on Mental Deficiency
(A.A.M.D).
The
American Association on Mental Deficiency system of classification. Mental
retardation refers to significantly subaverage gene?al intellectual functioning
existing concurrently with deficits in adaptive behaviour and manifested during
the developmental period.
"Significantly
subaverage" is defined as "approximately IQ 70 or below". This
implies an lQ test with a mean of 100 and a standard deviation of 15, eg,
Weschler. "Adaptive behaviour" relates to "the effectiveness or
degree with which individuals meet the standards of personal and social
responsibility expected for age and cultural group" and
"developmental period" relates to ages between birth and eighteen
years.
c) Someone who by reason of developmental
intellectual impairment needs additional services to lead a normal life or a
more normal life than would otherwise be possible.
Common threads
Low IQ.
Development onset
Impairment of social function
as judged against social norms, ie, it is both a
psychometric and a social construct.
lmpairment/ Disabilitv/Handicap WHO
Impairment
In
the context of health experience, an impairment is any loss or abnormality of
psychological, physiological, or anatomical structure or function.
Disability
ln
the context of health experience, a disability is any restriction or lack
(resulting from impairment) of ability to perform an activity in the manner or
within the range considered normal for a human being.
Handicap
In
the context of health experience, a handicap is a disadvantage for an
individual, resulting from an impairment or a disability, that limits or
prevents the fulfillment of a role that is normal (depending on age, sex and
social and cultural factors for that individual).
The terms impairment, disability and
handicap are often used interchangeably. The idea that a biological
abnormality that may or may not lead to loss of function that may or may not
lead to social disadvantage is, however, helpful. A biological deficit need not
always give rise to social dysfunction, where it does so it is because of
features in the society as well as the individual.
2.
Mental lmpairment
1983
Mental Health Act: Mental Impairment -
a state of arrested or incomplete development of mind which includes
significant impairment of intelligence and social functioning and impairment of
social and intellectual functioning associated with abnormally aggressive or
seriously irresponsible conduct.
1988
Local Government Act
A
person is severely mentally impaired if he has a severe impairment of
intelligence
and
social functioning, however caused which appears to be
permanent.
3. "Challenging Behaviour"
This
term is often used in the Learning Disability literature and increasingly elsewhere
in psychiatry. The intention is to draw
attention to the interactive nature of behaviour problems, some definitions
follow.
A small number of people who at
times exhibit behaviour which is so challenging that services have extreme
difficulty meeting their needs. The behaviours shown often involve aggression
to others, self injury, destruction of the environment or other distressing of
life threatening features which necessitate special provision.
Special
Development Team University of Kent
Severely challenging behaviour
refers to behaviour of such an intensity, frequency or duration that the
physical safety of the person or others is likely to be placed in serious
jeopardy, or behaviour which is likely to seriously limit or delay access to and
the use of ordinary community facilities.
From Decreasing Undesirable
Behaviours
G.
Murphy and C. Oliver Yule and Carr 1987
A behaviour may be a problem if it
satisfies some or all of the following criteria:
1. The behaviour itself or its severity is
inappropriate given a person's age and level of development.
2. The behaviour is dangerous either to
the person themself or to others.
3. The behaviour constitutes a significant
additional handicap for the person by interfering with the learning of new skills
or by excluding the person from important learning opportunities.
4. The behaviour causes significant stress
to the lives of those who live and work with the person and impairs the quality
of their lives to an unreasonable degree.
5. The behaviour is contrary to social
norms.
E. Zarkowska
and J. Clements 1988
Any pattern of action which
represents an inappropriate, persistent response to internal or external
stimuli; which is resistant to change; and which is detrimental to the
individual or his mileu.
Lowry and Sovner 1991
Problem behaviour is any behaviour
that needs to become less frequent or less marked, usually because it creates
difficulty for the person showing it or for others.
Presland 1991
1. The disturbed person behaves in an
idiosyncratic manner and the goals and motives of his actions are either inappropriate
or idiosyncratic. In other words we
have difficulty understanding disturbed behaviours.
2. The person's actions conflict with the
smooth functioning and norms of
relevant
social groups.Behaviour disturbances create management problems.
From Leudar and Fraser in Hogg and Raynes
1987 Common Themes
COMMON
THEMES
"Challenging
behaviour" is a social construct. It is defined in relation to socially
normal' behaviour and the appropriateness of the behaviour in a social context.
It is defined in terms of its effects on others as well as the person
exhibiting it. The cause of the behaviour is not crucial to the definition -
the events triggering the behaviour may be internal, external or unknown. Similarly any underlying predisposition to
challenging behaviour may be found in the individual, the setting or both. The term challenging behaviour neither
necessitates nor excludes a formal psychiatric diagnosis.
C.B.
is a mismatch between the behaviour an individual exhibits and the social
expectations for that individual.
Three
broad sub groups can be identified.
a) People who are mentally ill and whose
behaviour causes difficulties in management.
b) People who are behaviourally disturbed
in whom no psychiatric disorder is identified.
c) People who offend, who may or may not
have a mental illness.
Prevalence
Prevalence
of severe learning disability
The
prevalence of moderate to profound learning disability is roughly 3 per
1,000 and of mild learning disability
about 3 per hundred.
Prevalence
of psychiatric disorders among people with learning disability
Estimates
vary according to the age and location of the populations studied, the
definitions of both psychiatric disorder and learning disability; and the
instruments used. Most studies show people with learning disabilities to have a
significantly higher life time prevalence of psychiatric disorders. This is true even with population based
studies.
Studies based in Mental Handicap
hospitals tend to show higher prevalence rates. This may be because
1. Behavioural or psychiatric problems may
have led to admission.
2. The underlying pathology led to both
hospital admission and psychiatric disorder.
3. The institutional environment led to
behavioural or psychiatric problems.
4. People in hospital who are
behaviourally or psychiatrically disturbed are least likely to be successfully
discharged. Resettlement programmes
tend to favour those with the least complex problems.
Aetiology
of Psychiatric Disorder in people with biological. psychological
and
social learning disability
This
may be divided into Biological, Psychological and Social Biological
Genetic
Down’s
syndrome significantly associated with Alzheimers both clinically and on
neuropathology.
Tuberous sclerosis and various other
conditions show higher than expected rates of autism and pervasive
developmental disorders.
Behavioural phenotypes eg,
Prader_Willi partial deletion Chromosome 15 overeating, massive obesity. Lesch Nyhan self injurious behaviour which is associated with a defect
of uric acid metabolism.
FragileX -some family merbers have learning
disability and a fairly characteristic behavioural presentation, others have
raised rate of psychiatric illness but no learning disability.
Many people with learning disability
who present with malor functional illness have a strong family history of
psychiatric illness. Because of its
social and psychological aspects learning disability may increase an
individual's vulnerability to genetic loading.
Epilepsy
Associated with increased rates of
psychiatric disturbance. This is probably due to a combination of neurological
and social factors.
Physical
illness
May
present as disturted behaviour or predispose psychiatric illness.
Sensory
Impairment
Likewise
may cause disturbed behaviour or be a risk factor for psychiatric illness.
About one in four adults with a learning disability has a significant hearing impairment.
Prescribed
medication
People
with Learning Disability are likely to be prescribed drugs e.g., for epilepsy
or disturbed behaviours that have psychiatric and motor side effects. Sedative anti-epileptic drugs
(phenobarbitone, phenytoin) can produce drowsiness, paradoxical
over-arousal or pseudodementia. Vegabatrin may cause psychosis
which can present disturbed behaviour. People with Learning Disabilities
may be particularly sensitive to the motor side effects of neuroleptics.
Psychological
Poor
communication skills
Predispose
to frustrations, loss of motivation, challenging behaviour and
psychiatric illness. They also lead to misunderstandings and the mis
diagnosis of psychiatric illness.
Limited range
of coping behaviours
Lead to
increased vulnerability to psychosocial stressors.
Low self
esteem:
Secondary to parental loss and
disappointment; the experience of repeated failure and social marginalisation
and stigmatisation. This is an established risk factor,
especially for depression.
Lack of a theory of mind:
Though not
everyone with autism has a learning disability the majority do. The inability
to understand and predict the behaviour of others and everyday social rules
often leads to disturbed behaviour and may predispose to psychiatric illness.
Social
Biological
Impairment:-
May mean
that people are often unable to live independently or to find work. They often
have increased expenses and low income.
Labelling:-
Being labelled "mentally
handicapped" or "learning disabled" may itself lower self esteem
and predispose to psychiatric illness. It also often leads exclusion from
opportunities for employment, adequate income, leisure activities, marriage and
a valued social role.
Labelling
Thus both
impairment and labelling may restrict peoples access to known protective
factors. It may also lead to people
living in very unusual and restrictive family or institutional settings.
Loss
People
who are dependant on others may be more vulnerable to the effects of loss
especially of a care taker. Disturbed behaviour can be clearly shown to follow
loss life events but carers and others often deny that the person with learning
disabilities is aware of the loss. They may thus be denied the opportunity to
grieve which compounds the problem.
The
development of sexuality may also be ~ This may lead to someone being diagnosed
as sexually deviant when in fact they are merely uneducated and incompetent.
Sexuality
People
with learning disability, both adults and children, are at increased risk of
sexual abuse and its sequelae.
Assessment
and Diagnosis
Social
Context is extremely important. Very often the person with learning disabilities does not present
himlher self to the psychiatrist - it is the concern of the family or
professionals in day and residential care settings that brings them to
psychiatric attention.
Assessment
should include assessment of the wider system.
History
should be obtained both from the person with learning disabilities - if
communication skills permit - and from an informant or informants. Particular point of interest include -
Mothers reproductive and obstetric history.
Family
history Childhood - including mile stones. Aetiology of the learning
disability.
How were
family told and how did they respond?
Highest
level of functioning.
Do not assume that a low level of functioning is caused by the learning
disability per-se.
History of
presenting complaint. Particular attention to behavioural correlates of
psychiatric illness, eg, sleep, appetite, level of activity, interest in
previous pursuits (however limited).
Mental
State Examination
(Can be
done even in someone with no functional language. Includes dress, posture, communication style, behaviour
during the interview, response to particular people or subjects of
conversation.
May need
to be brief, may need to be repeated. May need informant to be present.
May use drawings
or toys.
Mental
state information should also be elicited from informant.
Behavioural
recordings
Recordings
of target behaviours e.g., sleep, aggressive outbursts by an informant over
time may both facilitate diagnosis and enable monitoring of treatment, whether
the intervention is behavioural, psychodynamic or pharmacological. Functional
behavioural analysis may be useful.
Physical
examination/ Investigation
Particularly
important in people who cannot complain.
Pain or discomfort often presents behaviourally. Hypothyroidism is
associated with Down's Syndrome and may mimic depression or dementia. Sensory
assessment is essential.
Specific
Conditions
Affective
disorders:-
Major
depressive disorder occurs and can be reliably diagnosed at all IQ levels.
Both
physical and psychological interventions can be used.
Mania
also occurs, but should be differentiated from other causes of over activity.
Individualised
recording schedules are particularly useful in managing cyclical
disorders.
Schizophrenia
The
relationship between schizophrenia learning disability and autism has been a
recurring debate in psychiatry (see Turner).
It
seems that people with learning disability experience increased rates of
schizophrenia which tend to be higher the lower the IQ, but that it cannot
reliably diagnosed (though it probably does occur) below IQ approximately
45. Below this level a diagnosis of psychosis not otherwise specified may
be important.
Dementia
Alzheimers,
especially the pathological as distinct from clinical features, occurs with
very high frequency in middle aged people with Down's Syndrome. Deafness,
hypothyroidism and depression are also common in this group. The exclusion of treatable conditions is
essential. Dementia presents as loss of skills. Psychometric diagnosis may be
difficult unless the results of adult, premorbid, testing are available.
Eatina
Disorders
Anorexia
nervosa has been described, usually in association with
depression.
Profoundly
disabled, multiply handicapped people may develop failure to thrive that
is
more like that otherwise seen in infancy.
Obsessive
Compulsive Disorder
Repetitive
ritualised behaviour is common. It is often life long and
associated with social ~~~~pairment and language abnormalities. Wing argues
that the term OCD be used only for a new condition that develops in a normally
sociable person with learning isability.
Adiustment
reactions
Social
marginalisation, social isolation, physical dependency and the way in which
services are organised all make people with learning disabilities more
vulnerable to the adverse effects of loss life events. The changes are often greater than for other
people and denial often compounds the problem. The presentation may be
behavioural. Counselling techniques, using pictures and objects as
well as words are effective.
Prevention involves the education of families and services.
Autism
A
diagnosis of autism does not preclude the diagnosis of other psychiatric
disorders (except, according to some schedules, obsessive compulsive disorder).
However, the motor phenomena, language pathology and social impairments of
autism may lead to over diagnosis of schizophrenia.
Hyperkinetic/Attention
deficit disorder
Thought
to be more common in people with learning disability and more likely to persist
into adulthood. Some overlap with "organic" personality disorder.
Personality
Disorders
Occur
especially "organic personality syndrome" DSM IIIR.
This
comprises affective instability, outbursts of rage or aggression, impaired
social
judgment,
apathy or suspiciousness in the context of specific organic impairment.
The
Diagnosis of Psychiatric Illness
Language
Where
there is no spoken or signed language it is not possible to diagnose delusions,
hallucinations or obsessive compulsive phenomena reliably. This does not mean
that they can not occur.
Even
when there is language it may be impossible to distinguish between a wish; an
over valued idea, and a delusion or between a day dream, a pseudo hallucination
and a hallucination. Sometimes an interpreter who knows the client well may
help.
Intervention.
Treatment and Management
Social,
psychological and physical interventions can be used. Effectiveness may be
assessed behaviourally.
People
with learning disabilities can make use of individual and group psychotherapies
as well as interventions directed at the setting or the antecedents or
consequences of behaviours. Evaluation of psychotherapy outcomes is similar to
that seen in other groups. Where
complete remission cannot be achieved a communicable plan of management should
always be attainable. Interventions
often involve the wider system.
Drug
therapies include the usual regimes though regular review and particularly
careful monitoring of side effects is essential. Carbamazepine may be used for
its behavioural effects and .in rapid cycling bipolar disorder as well as an
anti-epileptic drug. Sodium valproate is also used as a mood stabilising drug.
A
variety of drug treatments, including opiate agonists and antagonists is used
for self injurious behaviour, though in every case it is first necessary to
make a formulation including instigating, maintaining perpetuating features
which may be internal or external.
PREVALENCE
OF PSYCHIATRIC DISORDER IN PEOPLE WITH LEARNING DISABILITIES
EPIDEMIOLOGICAL
STUDIES
ADAPTED
FROM BREGMAN 1991
|
|
|
|
|
%
psychiatric disorder |
|
|
Study |
Age |
Sample |
Method |
PLD |
Controls |
|
Rutter
et al |
9-11 |
Enitre
age cohort |
Comprehensive
assessment Multiaxial |
30%-42% |
6%-7% |
|
Gillberg
et al |
13-17 |
Representative
cohort |
Comprehensive |
57%
(mild) |
5% |
|
Jacobson |
All
ages |
Receiving
services |
Survey
of behaviour frequency data |
14%
(children) |
None |
|
Lund
1985 |
>
20 |
Sample
from Danish MR register |
Comprehensive |
27% |
None |
|
Gostason |
20-60 |
Sample
from Swedish register |
Comprehensive |
33%
(mild) |
23% |