Institute of Psychiatry, De Crespigny Park, London
Hester Adrian Research Centre, University of Manchester, Manchester, UK
Correspondence: Steve Moss, Institute of Psychiatry, Department of Health Services Research, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
Declaration of interest The project was funded by grants from the Department of Health.
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ABSTRACT |
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Aims To determine what proportion of people with challenging behaviour actually have psychiatric symptoms.
Method Using an instrument specifically designed for use by informants, a sample of 320 people with administratively defined learning disability, with and without challenging behaviour, was surveyed for the presence of psychiatric symptoms.
Results Increasing severity of challenging behaviour was associated with increased prevalence of psychiatric symptoms, depression showing the most marked association. Anxiety symptoms were associated with the presence of self-injurious behaviour.
Conclusions There is clearly the potential for reducing challenging behaviour by improved identification and treatment of coexisting psychiatric disorders. The possibility of modifying diagnostic criteria for depression in people with learning disability, by including aspects of challenging behaviour, merits attention.
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INTRODUCTION |
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METHOD |
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Because the incidence of challenging behaviour decreases markedly in later life, the confounding effect of age was minimised by restricting the investigation to people under 60 years and matching by age bands. Because IQ is also a powerful confounder, the samples were stratified by their level of speech, as an approximate measure of intellectual level. There was no significant difference between the proportion of males in the sample groups.
Derivation of the samples
In 1988, seven district health authorities in the area then covered by the
North West Regional Health Authority participated in a total population survey
of the extent and nature of challenging behaviour among people with learning
disability (Qureshi & Alborz,
1992; Kiernan & Qureshi,
1993). The study included individuals with challenging behaviour
from age 3 to 87 years. A further study was undertaken in 1995
(Emerson et al, 1997).
This involved: the attempted follow-up of all people identified in 1988 as
showing more severe challenging behaviour; a repeat of the total population
screening in two of the seven districts; and the attempted follow-up of all
people identified in 1988 as showing less severe challenging behaviour. The
current investigation uses the 1995 data on those individuals who were between
18 and 60 years of age at the time of follow-up (n=234).
A control group (n=86) was drawn from a study of the health needs of 200 people with learning disability, commissioned by Tameside Learning Disability Services. The control sample was drawn from those individuals living in staffed accommodation, because there were few missing cases (in comparison with those living alone or with family members). Those individuals identified on the Wessex Scale (Kushlick et al, 1973) as having no challenging behaviour were randomly selected and age-matched to produce the same age banding as in the challenging behaviour study. Those in the latter study tended to be younger than the Tameside population, so the selection was achieved by randomly removing Tameside cases from the upper age bands to achieve the same proportions.
Information collected
Challenging behaviour
A full account of the extensive information collected in this sample can be
found in the report by Emerson et al
(1997). Sample members in the
challenging behaviour studies were rated on four basic types of challenging
behaviour: aggression; destruction of property; self-injury; and other
unacceptable behaviour. Each of these types was rated on a four-point scale
(serious, controlled, lesser, no problem). Overall severity of challenging
behaviour was estimated using a compound dichotomous variable (less
demanding/more demanding) derived from other information collected on the
sample members. A client was coded as more demanding if any of
the following applied:
Level of learning disability
There were no formal measures of intellectual ability collected on the
sample members. However, a strong indication could be inferred from sample
members' level of speech. In both the challenging behaviour study and the
control group this was measured on a three-point scale (no language, words and
phrases, full sentences).
Psychiatric symptoms
The Psychiatric Assessment Schedule for Adults with a Developmental
Disability (PAS-ADD) Checklist (Moss
et al, 1998) is a screening instrument designed to
identify mental health problems in people with learning disability. In both
the challenging behaviour and the Tameside study, a PAS-ADD Checklist was
completed for each sample member by an individual (staff member or family
member) judged to be in the best position to rate the symptoms. The PAS-ADD
Checklist has a four-point rating scale, designed to be the best compromise
between the loss of information resulting from a binary scale and the
unreliability resulting from too many points. However, because the
psychometric properties of the four-point scale were not known, a conservative
analysis was performed, items being dichotomised into symptom
present/absent.
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RESULTS |
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Speech results indicated that there was an expected strong association between level of challenging behaviour and level of learning disability (see Table 1). Most of the 234 individuals in the two challenging behaviour groups showed aggressive behaviour of various kinds, including self-injurious behaviour. However, 57% of the people in the study (n=133) did not manifest any self-injurious behaviour at all. As expected, those who did manifest self-injury (n=101) included a significantly larger proportion of individuals with no speech (see Table 2).
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Group comparisons of psychiatric symptomatology
Increasing severity of challenging behaviour was strongly associated with
the mean number of psychiatric symptoms (range 0-16) scored on the PAS-ADD
Checklist: no problem, n=1.4; less demanding, n=2.0; more
demanding, n=4.3; p < 0.0001 (Kruskal-Wallis test).
Post hoc comparisons using the Mann-Whitney test indicated that the
difference between the group without challenging behaviour and the group with
less demanding challenging behaviour was not significant. The difference
between the groups with less and more demanding challenging behaviour was
highly significant (P < 0.0001).
Table 3 gives details of the individual symptoms in relation to each level of severity of challenging behaviour. It can be seen that for 23 of the 26 items the prevalence was highest in the group whose challenging behaviour was more demanding.
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Four diagnostic categories were then derived from the PAS-ADD scores: anxiety, depression, hypomania and psychosis. In relation to anxiety, depression and psychosis it was possible to identify items on the schedule whose diagnostic significance was very clear-cut. With regard to hypomania, the core symptom in the PAS-ADD Checklist is elevated mood. However, the diagnostic significance of this symptom was not considered to be sufficiently clearcut, so for the present purpose individuals with probable hypomania were defined as those with elevated mood in conjunction with reduced need for sleep (either broken sleep or early waking). Core symptoms were thus as follows: anxiety phobic anxiety, non-situational anxiety; depression depressed mood, suicidal intent/actions; hypomania elevated mood plus early waking or broken sleep; psychosis hallucinations, delusions.
Table 4 shows the prevalence of individuals who either had at least one core symptom in the anxiety, depression or psychosis symptom groups or met the criteria for hypomania. These results show the prevalence of psychiatric disorders to be high in the whole sample and very high in the group with more demanding challenging behaviour. All four categories showed an increasing prevalence with severity of challenging behaviour, although this did not reach significance in the case of anxiety and psychosis. Depression showed a very marked prevalence that was differential across the three groups. For the whole study, the overall prevalence of psychiatric disorders is in accord with other published studies (Campbell & Malone, 1991).
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Self-injurious behaviour
Within the 234 people in the challenging behaviour groups, the prevalence
of PAS-ADD symptoms in people with and without self-injurious behaviour was
investigated. In terms of the mean total number of psychiatric symptoms
identified by the PAS-ADD Checklist, there was no significant difference.
However, four individual symptoms showed significant differences in prevalence
(Table 5).
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The sympton odd gestures and mannerisms probably features because people with self-injurious behaviour include a higher proportion of individuals with profound learning disability, many of whom demonstrate stereotyped behaviour. However, two of the symptoms are indicative of the fact that anxiety disorders are a possible factor in self-injurious behaviour (jumpy and phobic anxiety).
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DISCUSSION |
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Challenging behaviour as a possible diagnostic criterion for
depression
Some authors (e.g. Meins,
1995) have suggested that challenging behaviour can sometimes be
an atypical expression of depression and should be incorporated into
diagnostic criteria modified specifically for this population. Although the
results from the current study suggest that this assertion merits attention,
it may be difficult to implement in practice. The determinants of challenging
behaviour are likely to be highly complex a combination of factors
relating to history of learned behaviour and biological, environmental, social
and psychological factors. Challenging behaviour may exacerbate a coexisting
psychiatric disorder, whereas psychiatric disorders may express themselves
partly in terms of a challenging behaviour. Given this complexity, the use of
data on challenging behaviour to make psychiatric diagnoses would pose major
questions of validity.
Self-injurious behaviour
Among people with self-injurious behaviour, anxiety disorders were
identified as being more prevalent than among people without such behaviour.
It is not clear whether this finding relates specifically to the presence of
self-injurious behaviour or whether it is because this group contains more
individuals with profound learning disability. It has been noted elsewhere
(King et al, 1994)
that anxiety disorder is one of the most frequent diagnoses made in people
with this level of disability.
Reliance on untrained raters
A potential limitation of the current study was that the information on
psychiatric disorders was provided exclusively by non-psychiatrists. Although
the PAS-ADD Checklist has been validated for use by unqualified observers
(Moss et al, 1998),
accurate quantification of the statistical associations between challenging
behaviour and psychiatric disorders would need a further study using
comprehensive multidisciplinary assessment, including expert psychiatric
opinion.
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Clinical Implications and Limitations |
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LIMITATIONS
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REFERENCES |
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Cambell, M. & Malone, R. P. (1991) Mental retardation and psychiatric disorders. Hospital and Community Psychiatry, 42, 374-379.[Medline]
Emerson, E., Kiernan, C., Alborz, A., et al (1997) The HARC Challenging Behaviour Project. Summary. Manchester: Hester Adrian Research Centre.
Emerson, Moss, S. C. & Kiernan, C. K. (1999) The relationship between challenging behaviour and psychiatric disorders in people with severe intellectual disabilities. In Psychiatric and Behavioural Disorders in Mental Retardation (ed. N. Bouras), pp. 38-48. Cambridge: Cambridge University Press.
Felce, D., Lowe, K., Perry, J., et al (2000) Service support to people with severe intellectual disabilities and the most severe challenging behaviours in Wales: prevalence, outcome and costs. Journal of Intellectual Disability Research (in press).
Goldberg, D. & Huxley, P. (1980) Mental Illness in the Community. London: Tavistock Publications.
Kiernan, C. & Qureshi, H. (1993) Challenging behaviour. In Research to Practice? Implications of Research on the Challenging Behaviour of People with Learning Disabilities (ed. C. Kiernan). Kidderminster: British Institute of Learning Disabilities.
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Meins, W. (1995) Symptoms of major depression in mentally retarded adults. Journal of Intellectual Disability Research, 39, 41-45.[Medline]
Moss, S. C., Prosser, H., Costello, H., et al (1998) Reliability and validity of the PAS-ADD Checklist for detecting psychiatric disorders in adults with intellectual disability. Journal of Intellectual Disability Research, 42, 173-183.[CrossRef][Medline]
Patel, P., Goldberg, D. & Moss, S. (1993) Psychiatric morbidity in older people with moderate and severe learning disability. II: The prevalence study. British Journal of Psychiatry, 163, 481-491.[Abstract]
Prosser, H., Moss, S. C., Costello, H., et al (1998) Reliability and validity of the Mini PAS-ADD for assessing psychiatric disorders in adults with intellectual disability. Journal of Intellectual Disability Research, 42, 264-272.[CrossRef][Medline]
Qureshi, H. & Alborz, A. (1992) Epidemiology of challenging behaviour. Mental Handicap Research, 5, 130-145.
Received for publication July 7, 2000. Revision received May 30, 2000. Accepted for publication June 9, 2000.