The UK Government White Paper ‘Valuing people’ estimates that there are about 2 10,000 people with severe and profound intellectual disabilities in the UK: around 65, 000 children and young people, 1 20,000 adults of working age, and 25, 000 older people. They estimate that there are some 1.2 million people in the UK with mild or moderate intellectual disabilities. Worldwide, it is estimated that there are some 20 million people with intellectual disabilities.⁽²⁾

Although there is now a trend in the UK towards mainstreaming children with special needs, and providing extra support, separate special schools for children with moderate and for severe learning difficulties are still provided in many places. At school leaving age, many young people with mild or moderate learning difficulties (roughly equating to IQ > 50) will not receive special services; only people who have severe intellectual disabilities, and those with additional disabilities, including epilepsy, autism, mental illness and/or behavioural problems will be referred on to adult specialist services. The administrative prevalence of adults with intellectual disabilities is thus much lower in adulthood as it is a measure of those in contact with services. The administrative prevalence rates should not be confused with true prevalence rates, which are far more difficult to assess.

Among young people in the general population, there are certain important life events which are usually considered necessary for a successful transition to adulthood. These include getting a job or going to college, having economic and social independence from parents, and leaving home.⁽³⁾ Although the transition to adulthood can be a difficult and painful process for anyone, for most people it is also a time at which choices and opportunities open up. For people with intellectual disabilities, the transition to adulthood does not usually follow the same pattern as it does for others. For many, the transition is marked simply by an abrupt move from the protective and relatively well-defined children’s services to adult services, and by leaving school. These imposed transitions into adulthood are often abrupt and traumatic for the young people and for their parents.⁽⁴⁾

Overall, the criteria for ‘successful’ transition to adulthood are less likely to be fulfilled the greater the severity of the intellectual disability and other factors such as physical or mental health problems, communication difficulties and/or challenging behaviour. Those who have mental health problems, or aggressive challenging behaviour, are particularly unlikely to receive the necessary support and services to enable them to live independent ‘adult’ lives.⁽⁵⁾ In 2001, a new service, Connexions, was established to improve the management of the transition to adulthood, by providing young people from 13–19 years of age with access to advice, guidance and support.⁽²⁾

In the UK, the majority of young people with intellectual dis abilities attend Day Centres. Those who are more able may enter sheltered employment, workshops for disabled people or supported open employment. Relatively few people with intellectual disabilities are in paid employment, and although employment schemes are now being developed in many places, there are substantial barriers that are faced by people with intellectual disabilities in getting and maintaining employment in the open job market.⁽²⁾

In all parts of the world, the majority of young people with intellectual disabilities continue to live at home with one or both parents, and often have little or no social or economic independence, or participation in major, or even minor, life decisions. Although adolescence and leaving school imply a transition to adulthood, in many cases young people become more dependent
on their parents at this stage than they were before. For those who have severe or multiple disabilities, and/or challenging behaviour, there may be few practical alternatives and choices open to them.⁽⁶⁾

In different countries, various approaches have been developed to recognize the needs of young adults. One widely adopted approach, the development of small group homes in the community, has meant that more young people with intellectual disabilities are able to move away from home, even some who have severe intellectual disabilities and challenging behaviour. In many countries however, the responsibility remains firmly with carers, with institutional provision being the only backup when family care breaks down. An international carers’ advocacy organization, Inclusion International, researched the views of carers in 80 or more countries in both developed and developing nations, and their report makes a number of recommendations about how communities and governments can provide better support to individuals and families.^{(7, 8)}

There is a high prevalence of epilepsy, psychiatric disorder, hearing and visual impairments and autism among people with intellectual disabilities. Children with intellectual disabilities are the responsibility of a paediatrician, and parents can discuss and monitor their children’s needs and progress through one agency. When a child is transferred to adult services this situation changes, and there are many different agencies and individuals who become responsible for different aspects of the overall service to adolescents.

For the families concerned, the world of adult services can be bewildering. The situation is particularly problematic in relation to adolescents with severe intellectual disabilities, especially if there are also behaviour problems, during this transitional phase from child to adult services. Impairments in adaptive behaviour associated with intellectual disability lead to problems in developing normal social functioning, communication, and the ability to use community facilities. In addition, the relationship between parental and professional roles and responsibilities is often unclear. Multidisciplinary assessment is advisable, and parents should remain involved, but all too often are told that their opinion is no longer valid now their child is an adult.⁽²⁾ The Royal College of Psychiatrists publishes leaflets for family carers to help them manage these changing professional relationships.⁽⁹⁾

It is often not apparent who, among the professionals, is directly responsible for someone in the context of services, and there may be inconsistencies between Health, Education, and Social Services in terms of policies and practice. Also, health professionals, including general practitioners, may be relatively inexperienced in dealing with people who have intellectual disabilities.

A coherent strategy for developing comprehensive health care services for young people with intellectual disabilities requires collaboration between service providers, to ensure that the health care needs of all people with intellectual disabilities, including those with autism, are properly identified, and that access to mainstream primary and secondary health care is supported. One initiative developed for the white paper ‘Valuing people’ was the introduction of Health Action Plans to try to address some of these information and knowledge gaps.⁽¹⁰⁾

Diagnostic overshadowing of mental illness in people with intellectual disabilities was common in the past, but there is now increasing awareness and assessment of psychiatric disorders, and acceptance of dual diagnosis among people with intellectual disabilities. Although mental health needs can in some cases be met by general mental health services, some specialized mental health provision is still necessary to meet the needs of people with dual diagnosis, including those who also have challenging behaviour.⁽¹¹⁾

Until recently, people with intellectual disabilities were seldom thought to suffer from depression, but recent research shows that adolescents with intellectual disabilities report more depression and other symptoms of psychopathology than others without intellectual disabilities.⁽¹²⁾

There is increasing awareness, and continuing evidence,^(13,14) of the high prevalence of abuse of people with intellectual disabilities, of all ages, including emotional, physical, and sexual abuse, resulting in Post Traumatic Stress Disorder,⁽¹⁵⁾ severe behavioural disorders⁽¹⁶⁾ and damaging long term effects on the family as a whole.⁽¹⁷⁾ Challenging behaviour in people with intellectual disabilities may be indicative of psychiatric disorders, such as psychosis, depression, and anxiety disorders.

A recent report concludes that people with intellectual disabilities who present behavioural challenges are often marginalized, stigmatized, disempowered, and excluded from mainstream society,⁽¹⁸⁾ indicating the need for changes in policy and practice.

Long-term sexual relationships and parenting children are generally considered to be an integral part of being an adult. In adolescence, emotional and sexual interest and needs develop, and it is at this stage that most young people start to have sexual relationships. However, people with intellectual disabilities are seldom encouraged to develop sexual relationships. Parents tend to actively discourage it, and service managers and care staff, though they may not necessarily actively discourage it, often provide little opportunity, or privacy, to enable it to happen. Many people in the general population find it difficult to accept that men and women with intellectual disabilities have ordinary sexual feelings and desires, let alone that they should be allowed to act on them.⁽¹⁹⁾ The argument against allowing people with intellectual disabilities to have sexual partners often involves judgments about whether someone is deemed fit to be a parent. People with intellectual disabilities are discouraged from parenthood, and the experiences of childbearing and child rearing are still usually denied to women with intellectual disabilities. In Norway, 40 per cent of a study cohort of 126 children born to parents with intellectual disabilities were found to have suffered from ‘failures of care’.⁽²⁰⁾ In England, however, research has demonstrated that some people with intellectual disabilities can become successful parents, provided they are given appropriate and effective support.⁽²¹⁾