http://bmj.com/cgi/content/full/323/7313/633
BMJ 2001;323:633 ( 15 September )
Letters
Prevalence of autism in early 1970s may have been underestimated
Recently,
concerns about an apparent increase in the prevalence of autism in the general
population, and the pathophysiology behind this, have been prominent
in the press. Before these concerns can be addressed we need to be
sure that the prevalence has truly increased. A cohort study was
thought suitable to provide an insight into whether the prevalence
of autistic disorders has increased.
In the British cohort 1970 study (BCS70) only five children were
identified as having autism (and one as having suspected autism) at
the age of 5 in disability data files. This gives a prevalence
of 6/13 135 (0.45/1000)comparable
with that found in previous studies. 1 2
A focus group consisting of practising consultants (from adult and
paediatric disciplines) experienced in the diagnosis of autistic
disorders was convened. This group identified several diagnostic
features from the available data that they thought were important in
making a diagnosis of autistic spectrum disorder. The aim was to
identify whether there were missing or undiagnosed cases with
current commonly used diagnostic features. The features identified
from the original BCS70 questionnaire included:
- At age 5
Restless
Solitary; does things on own
Fearful, afraid of new situations
Fussy or over particular - At age 10
Does things on own; rather solitary
Afraid of new situations
Fussy or over particular
Hums or makes odd noises
Obsessional
Requests must be met immediately
When an analogue scale was used, only the most extreme casesthat
is, the top fifthwere
identified. Cases in which the child had all features present at
both age 5 and age 10 were then identified.
Using the methodology above, we identified 56 cases from 14 904
children studied at age 10, giving a prevalence of 3.76/1000. This
suggests that these children have an autistic spectrum disorder when
contemporary diagnostic features are used.
Our finding agrees with current lifetime prevalence figures suggested by
Powell et al.3
Thus estimates of prevalence from the early 1970s may have seriously
underestimated the prevalence at that time. Confirmation of this
suggestion would require contemporary assessment of the individuals
involved.
Helen Heussler
honey.heussler@nottingham.ac.uk
Leon Polnay
Division of Child Health, School of Human Development, University of
Nottingham, Nottingham NG7 2UH
Elizabeth Marder
Department of Paediatrics, Queens Medical Centre, Nottingham NG7 32UH
Penny Standen
Division of Rehabilitation and Ageing, School of Community Health Sciences,
University of Nottingham
Chin Lyn U
Division of Psychiatry, School of Community Health Sciences, University of
Nottingham, Nottingham NG3 6AA
Neville Butler
80 Cumberland Road, Bristol BS1 6UG
|
1. |
Gillberg C, Wing L. Autism: not an extremely rare
disorder. Acta Psychiatr Scand 1999; 99: 399-406 |
|
2. |
Kaye J, del Mar Melero-Montes M, Jick H. Mumps, measles,
and rubella vaccine and the incidence of autism recorded by general
practitioners: a time trend analysis. BMJ 2001; 322: 460-463 |
|
3. |
Powell J, Edwards A, Edwards M, Pandit B, Sungum-Paliwal
S, Whitehouse W. Changes in the incidence of childhood autism and other
autistic spectrum disorders in preschool children from two areas of the West
Midlands. Dev Med Child Neurol 2000; 42: 624-628 |
|
Rapid Response responses to
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responses
focus groups are now considered science?
Mark F. Blaxill , Boston MA
bmj.com, 16 Sep 2001 [Response]
Other related articles in BMJ:
PAPERS
Mumps, measles, and rubella vaccine and the incidence of autism
recorded by general practitioners: a time trend analysis.
James A Kaye, Maria del Mar
Melero-Montes, and Hershel Jick
BMJ 2001 322: 460-463.