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634 Developmental Medicine & Child Neurology 2001, 43: 634–638
Adult outcome of childhood learningdisability
Greg O’Brien FRCPsych FRCPCH MD
Professor of Developmental Psychiatry, University of
Northumbria.
Correspondence to author at Northgate Hospital, Morpeth,
Northumberland, NE61 3BP, UK.
‘But what are the prospects for the future, Doctor?’ This ques-
tion is frequently asked by parents of children with learning
disability.* But longitudinal studies of the outcome in adult-
hood of childhood learning disability are lacking.1 At the same
time, extrapolating prognoses from the available evidence is
unreliable. Increasingly, however, clinicians are faced with this
basic question that is on the minds of parents who have
gleaned ‘information’ from other sources, notably the inter-
net. So, what can be usefully and reliably claimed regarding
outcome in adulthood for children with learning disabilities?
Outcome studies in learning disabilityStudies of the outcome of childhood learning disability have
adopted a variety of strategies. Various outcome measures
have been used including: (1) life expectancy, (2) general
health, (3) adaptive functioning, (4) psychopathology, (5)
service contact, and (6) integration into adult life. Early stud-
ies focused mainly on morbidity and mortality (e.g. Decker
and colleagues,2 Richards and Sylvester3), while more recent-
ly the emphasis has shifted towards systematic consideration
of quality of life .15, 18
Life expectancyThere is a long tradition of research on the mortality of people
with learning disability. A variety of studies (e.g. Richards and
Sylvester,3 Balkrishnan and Wolff 4) have demonstrated that, in
general, children with learning disability have a shorter life
expectancy than other children. Previously, most of these stud-
ies were carried out on long-stay hospital patients employing
case note data, but the same outcome has been found in the
recent community-based study by Hollins and colleagues,5 that
examined death certification data of individuals with learning
disability. These studies have clarified that mortality increases
with increasing severity of learning disability, most notably
among those with IQ levels below 40.5–7 Other high risk factors
which predict or are associated with earlier death in people
with learning disability include any additional physical disabili-
ty or medical problem, notably cerebral palsy and poorly con-
trolled epilepsy. Non-mobile children and those incapable of
self-feeding are especially at risk of short life expectancy.6
Another strategy has been to concentrate on the cause of
death among people with learning disability. In a major
50-year study Carter and Jancar8 found that before 1955, tuber-
culosis was a common cause of death among people with
learning disability while other respiratory infections were
implicated more commonly in later deaths. Between 1930 and
1980, death rates by arterial disease increased while death from
status epilepticus decreased. They also found that from 1959 to
1968, cancer became a more common cause of death among
people with learning disability. These three latter trends mir-
ror changes in lifestyle and improvements in medical treat-
ment of people with learning disability over the last 50 years.
Subsequently, Dupont and coworkers9 applied the concept of
‘avoidable mortality’ to learning disability. A cause-specific
mortality calculation was devised with the aim of demonstrat-
ing the extent to which mortality among people with learning
disability might be potentially avoidable. Accidents, including
choking to death, figured prominently here. There was little
tobacco and diet-related death among individuals with more
severe disabilities (IQ under 50) when compared with the gen-
eral population. Certain health problems which are more com-
mon among people with learning disability were particularly
associated with high mortality, namely major congenital mal-
formations. Recent trends toward the widespread application
of corrective surgery have contributed to reductions in this
type of mortality. More recently, meta-analysis has been
applied to the study of mortality among people with learning
disability. In a major review, Harris and Baraclough10 found
that learning disability was associated with a death risk 2.8
times higher than expected, and the mortality risk from
unnatural causes was 3.1 times higher. Seventy-eight percent
of deaths among the people with learning disability were
from unnatural causes, while only 22% were from natural
causes, the latter still carrying a 2.1 times higher risk.
General healthThere has been long-standing interest in general health out-
comes for children with learning disability. Indeed, early con-
cepts of ‘subnormality’ (such as that by Down11) emphasized
the extent to which eventual poor health was inextricably
linked to the nature of learning disability (reviewed in
O’Brien12). Where researchers have focused on general health
and morbidity, one widely adopted approach has been to
begin by identifying the major common health problems in
Annotation
*UK usage. US usage: mental retardation.
this population, and to proceed to closer consideration of
unmet health needs (e.g. the study by Decker and col-
leagues2). Studies of general health and morbidity in learn-
ing disability commonly employ disability registers, direct
assessment, or both. Disability registers offer the advantage of
a locally defined database including an account of the pres-
ence and severity of a selected set of common health vari-
ables.13 However, these registers are not necessarily regularly
updated and there is no common dataset between different
registers.14 The other general strategy, therefore, consists of
direct assessment of individuals according to a set of pre-
established criteria incorporating a standardized assessment
of specific health problems. One theme which has as yet
eluded researchers, however, is the development of a ‘posi-
tive health and well-being’15 measure for children with learn-
ing disability, because of the difficulties inherent in defining
this in the index population. Most initiatives, therefore,
remain problem based, concentrating on the measurement
of certain high profile and important general health outcome
variables for people with learning disability, for example,
those associated with epilepsy.15 The latter initiative now
offers the possibility of studying the quality of life of people
with learning disability who have major health problems,
where the opportunity for the individuals to make personal
choices and control their own circumstances is regarded as
central for general health outcome. Also, in consideration of
general health outcomes, a variety of important interactional
effects are apparent.16 For example, the child’s own percep-
tion of a physical illness, such as epilepsy, can play a crucial
role in outcome,17 as does family and parental adjustment to
the stress of disability.18–20
Adaptive functioningIn many instances, the first and the most fundamental question
is about which factors most powerfully influence subsequent
adaptive functioning in children with learning disability. This
issue can be further broken down into several subsidiary ones.
First, is there good evidence that the severity of learning dis-
ability in childhood (in terms of lower IQ) is of itself predictive
of subsequent social adaptive functioning? Reviewing this mat-
ter, Clarke and Clarke21 concluded that early severe learning
disability very powerfully predicts long-term dependency and
disability, much more than mild disability. In addition, the stud-
ies they reviewed indicated the importance of other child fac-
tors as predictors of subsequent adaptive functioning. Notably,
it was found that early conduct disorder was an important
adverse factor. A more recent review22 agreed that child vari-
ables are an important consideration of subsequent adaptive
functioning, but emphasized that a host of environmental vari-
ables are also crucially important. Studies of the social adapta-
tion of children with learning disability are potentially difficult
to design, given this combination of multiple intrinsic and envi-
ronmental influences. Many recent studies have therefore
focused on certain important high profile subpopulations of
children with learning disability, and on other informative sam-
ple groups. Galler and coworkers23 carried out a 15-year fol-
low-up of children who had experienced malnutrition in the
first year of life, to the extent that it resulted in measurable
intellectual disability in early life. Their follow-up study found
that early intellectual disability persisted into adolescence.
Similarly, Huttonlocher and Hapke24 followed up 145 patients
with intractable epilepsy, finding an association between early
learning disability and later adaptive functioning. In the same
vein, Steinhausen and colleagues25 performed a long-term
child-to-adult follow-up of 158 infants with foetal alcohol syn-
drome, finding that early intellectual disability had a powerful
effect on later intellectual outcome. The consensus which
emerges from these studies is that the severity of childhood
learning disability may be of itself a most powerful predictor of
later subsequent adaptive functioning in all subpopulations
with learning disability.
Faced with such a prospect, some reviewers have concen-
trated on how best to maximize social adaptive functioning of
children with learning disability. One long-standing debate
concerns patterns of parenting. Marfo26 noted that while it had
been widely believed that certain patterns of parenting such as
‘maternal directiveness’ (i.e. a proactive, directive style of par-
enting) were likely to have an adverse effect upon develop-
ment, this was in fact not based on empirical evidence. Another
possibility was that any such maternal directiveness is better
seen as an indicator of the severity of early intellectual and
behavioural challenges. In other words, a directive style of par-
enting may be a functional, adaptive response to behavioural
problems in a child, rather than the cause of the child’s difficul-
ties. However, it is generally recognized that maximal social
adaptive functional outcome for children affected by learning
disability is attained through careful, programmed interven-
tion. An illustrative example of this can be found in the work of
Hatton and colleagues27 which has demonstrated that contem-
porary specialized community-based care models do seem to
generate optimal global outcome.
PsychopathologyStudies of the outcome of learning disability in childhood have
been informative regarding the occurrence and nature of later
psychopathology. Bartak and Rutter28 in a comparative study of
children with autism, with or without learning disability, indi-
cated that severity of learning disability has a powerful effect on
both the nature and the eventual outcome of autism. Indeed,
reviewers of different outcome studies have long noted that
this is so, despite rigorous educational and therapeutic inter-
ventions (such as the work of Nakane29). Similarly, Havelkova
and coworkers30 performed a 15-year follow-up study of 20
‘preschool schizophrenic children’ (which in today’s language
corresponds to children with autism), demonstrating that chil-
dren’s preschool IQ was the most powerful predictor of later
psychiatric disturbance. Some caution is required in the inter-
pretation of such studies, as the IQ test result may well have
been affected by the presence of autism. Nevertheless, the pre-
dictive power of IQ in the context of autism is of interest itself.
This was corroborated by von-Knorring and Hagglof31 who
carried out a 9-year follow-up of individuals with autism,
including those with learning disabilities, concluding that the
symptoms of autism were remarkably constant over time.
One of the most convincing studies of the psychopatholog-
ical and behavioural outcome of child learning disability is
that of de Chateau.32 This was a 30-year follow-up of adminis-
trative records, which found that early (in 0- to 3-year-old
infants) difficulties in adaptive functioning predicted later
behavioural problems. Overall though, other factors were
identified as important determinants of outcome, particularly
sex of child and psychopathology in parents. These results are
in line with the major Cambridge Delinquency Study, which
found that low intelligence, poor academic attainment, and
Annotation 635
impulsive or antisocial behaviour in early childhood are
among the best predictors of subsequent delinquency, along
with non-child factors such as family criminality, poverty, and
adverse parenting.33
Service contactIt is to be expected that the nature and severity of learning dis-
ability will exert a substantial influence on service contact and
utility. Other factors, not the least of which is service availability,
636 Developmental Medicine & Child Neurology 2001, 43: 634–638
Table I: Outcome studies in learning disability
Type of study Nr of IQ in Outcome measures including: work; Study Author(s)participants childhood marriage; offending; residence; location
mental health; physical morbidity and mortality; developmental attainments
25-year postal follow-up,a 646 60–85 More able participants were in work USA Fernald45
after hospital discharge 10% of women and few men were married
Recorded convictions in 42% women, 10% men
Rehospitalization in 35% women, 24% men
4-year case-note study.b 50 Average 20% were in work USA Bronner46
Follow-up of attendees 68 80% had reoffended
at one child guidance clinic 20% were living independently
for delinquents
17-year case recordc 122 60–85 78% were in ‘totally-self-supporting’ USA Fairbank47
adult, follow-up of child ‘More multiple marriages’
learning disability ‘Excess’ of offending
Prospective blindd 84 50–90 Half were successfully employed in dressmaking USA Abel and
follow-up of young adults Kinder48
with learning disability
selected and prepared for
work experience
30-year, official recorde 626 70–84 Low IQ group: typically in unskilled jobs Sweden Ramer49
follow-up of children with and Lower marriage rate; higher divorce rate
learning disability born 589 Higher rate of institutionalization
1905–1917, and normal No cross-group differences in offending
control children
6- and 9-year, communityf 432 70–85 Work record ‘good’ Scotland Ferguson and
case note and interview ‘High rate’ of offending Kerr50, 51
follow-up of special school (Those who had been hospitalized were
leavers excluded)
Semi-structured psychiatric g 520 40–50 27% in employment USA Saenger52
interview of adults who had None married; 4% had sexual experience
been classed ‘trainable retard’ Offending ‘extremely uncommon’
as children 39% whole life rate of hospitalization; 25% current
Psychiatric status: 20% ‘neurotic’; 6% ‘psychotic’
75% had physical disability or infirmity
Controlled prospectiveh (1) 256 45–75 Compared with 129 normal IQ-matched control USA Kennedy 53, 54
follow-up of adult social individuals for other indices, including social
functioning adversity; index group had a ‘less satisfactory’
work record and higher offending rate, but no
difference in marital history.
(2) 179 Mean Compared with control participants, no difference
18 y later 99.5 in work, less marked higher offending rate,
same marital history
Controlled, prospectivei, j, k 1933: <70 1936: 27% in work; low marriage rate; 3–7 times USA Baller55
30-year case note and 206 increased rate of offending Charles56
interview follow-up of 1953: 36% in work; high divorce rate; 40% Baller, Charles
social functioning in 1964: offender rate and Miller57
adulthood, after childhood 100 1964: 67% in work; high divorce rate; 1/3 dead
educational failure by age 56 y (age-expected mortality 1/6)
Adult follow-up of childrenl 221 Mostly 89% in full-time employment Scotland Richardson
born 1952–1954, 22 y <70; 2/3 not in special (learning disability) and Koller58
‘administratively classified’ some service contact
as having learning disability <80
a1919; b1933; c1933; d1942; e1946; f1955, 1958; g1957, 1960; h1948, 1966; i1936; j1953; k1966; l1996.
will also figure. One influential study34 emphasized that expec-
tations, and particularly unduly over optimistic expectations
concerning the potential outcome of severe disability in young
people on the part of service planners, often play a crucial role
in service outcome. Most authorities would agree that factors
of family functioning in the area of coping and problem solving
are also important in determining future and ongoing service
contact and utility for children with learning disability. This has
also been demonstrated in experimental studies (e.g. Black
and colleagues35). Similarly, Schalock’s36 5-year follow-up of a
cohort of individuals with varying degrees of intellectual dis-
ability (n=108), found that both disability-related and environ-
mental-associated factors determined outcome in terms of
service utility, emphasizing the importance of degree of motiva-
tion and participation on the part of individuals’ families.
Considering the nature of service provision and the manner
of its delivery, there have been numerous studies of how differ-
ent types of services, such as patterns of day care, result in dif-
ferent patterns of contact/utility on the part of individuals
with learning disability. One interesting example was that of
Jacobson and colleagues37 who included certain employment
characteristics and work satisfaction in their study. Their results
suggested that both ‘engagement’ in work and the nature of
the work are powerful factors in determining work satisfaction
in individuals with learning disability. Other studies have con-
sidered how aspects of service management and the organiza-
tion of individuals’ care plans can affect service utility and
contact. Here, Schalock38 described a resource allocation
model of care planning which aimed to maximize outcome in
terms of service contact. A subsequent survey by O’Neill39 indi-
cated that planned, coordinated care does indeed seem to lead
to better service utility, considering postinstitutional outcome
in terms of daily living and day care. This finding was corrobo-
rated by Criscione and coworkers,40 whose 1-year follow-up
study found that programmed case management affected out-
come in terms of readmission to hospital.
It has long been recognized that the service careers of chil-
dren affected by any major disability, such as learning disability,
will inevitably be determined by a combination of interactive
factors. Reviewing this issue, Eisen41 suggested that a vulnera-
bility/stressor/resilience model might be useful. Here, severity
of disability and concurrent health problems might be seen as
vulnerabilities, life events, and changing circumstances and
(lack of) services might function as stressors, while markers of
resilience are most likely to be discerned in certain styles and
patterns of parenting and family functioning. Another range of
influences on outcome are those in the area of expectations: a
recent study by Wehmeyer42 highlighted how, for example,
locus of control, notably excessive external locus of control
(and a parallel conviction of being powerless over their own sit-
uation), can have the most powerful, detrimental effect on out-
come for people with learning disability.
Adjustment to adult lifeJust as the most commonly asked question concerns the
prospects for later development of children with learning
disability, the most fervently held hope is that the child will
enjoy a satisfying and fulfilling adult life, and in whatever
ways possible, a successful one. On these themes, once
again, the available follow-up studies indicate that many indi-
viduals will indeed enjoy futures which live up to these
expectations. But the bad news, once again, is inescapable;
as the various follow-up studies of such key indicators of adult
adjustment as employment, relationships, criminality, and
adult mental health do not give cause for optimism. Some of
the main follow-up studies are summarized in Table I. It is
notable that: (1) in respect of most outcome indices of general
integration into adult life, the child with more severe disabili-
ties is at greater risk; (2) the findings of early studies have been
substantially corroborated by more recent work; and (3) the
outcomes for children with mild learning disability have
improved in more recent years. It is this latter observation
which has been pivotal. Many workers derive much optimism
from Tizard’s43 appraisal of the situation of people with learn-
ing disability over the closing decades of the 20th century. He
perceived that the outcome and situation of people with mild
learning disability had improved so much, that it must only be a
matter of time before the same improvements would apply to
the situation of children with more severe learning disability.
Sadly, there are no signs of the emergence of such a fundamen-
tal change. On the contrary, all available evidence points
towards corroboration of Penrose’s key observation44 that the
more severe the child’s learning disability, the less promising
are the prospects.
In summary, while seeking to predict definitive adult out-
comes for an individual child with learning disability may be
folly, certain key issues are helpful. First, the severity of child-
hood learning disability in terms of IQ exerts a major influence
on subsequent development and adjustment. Secondly, the
presence of any major physical disability has a substantial bear-
ing on outcome. Furthermore, self-perception, parental and
family factors, and wider societal influences are important
mediators of these key biological variables. In clinical practice,
therefore, the task is to identify opportunities for intervention
in these various domains in order to promote maximal out-
comes for children with learning disability.
Accepted for publication 20th December 2000.
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638 Developmental Medicine & Child Neurology 2001, 43: 634–638
