Introduction

Approximately 2–3% of the general population has some form of intellectual disability (Department of Health, 2001). The prevalence of severe intellectual disability (IQ < 50) is 3–4 per 1000, and that of moderate intellectual disability (IQ 50–70) is 30–40 per 1000 (Felce et al, 1994).

There is abundant evidence that children with intellectual disabilities are at significantly increased risk of developing mental health problems (Dykens, 2000; Stromme & Diseth, 2000; Tonge & Einfield, 2000; Emerson, 2003; Whitaker & Read, 2006) and that this affects between 40 and 75% (Corbett, 1985; Gillberg et al, 1986; Wallace et al, 1995). Emerson & Hatton (2007) estimate that children with intellectual disabilities are six times more likely to have a diagnosable psychiatric condition than other children in Britain. They are also at increased risk of having specific disorders such as autism-spectrum disorders (Fombonne, 1998; Emerson & Hatton, 2007) and ADHD (Dykens, 2000). Mental health services for children and young people with an intellectual disability and their families should therefore be readily available and of a high quality. In the UK, the government (Department of Health, 1992) and the Royal College of Psychiatrists (1992) have long recognised this. Despite this and the fact that Standard 8 of the NSF for children states that Local Authorities, primary care trusts and CAMHS must work together to ‘ensure that disabled children have equal access to CAMHS’ (Department for Education and Skills & Department of Health, 2004), only 60% of primary care trusts had commissioned CAMHS for young people with intellectual disabilities in June 2006 (Department for Education and Skills & Department of Health, 2006). This chapter may therefore have a practical role to play as commissioners and services seek to address this gap in service provision.

Organisation of services

It is first necessary to decide where mental health services for children and young people with intellectual disabilities will sit organisationally. Historical models often placed such services within all age services for people with intellectual disabilities. It was argued that this gave rise to good continuity of care. In recent times, dedicated children's services have become accepted as more appropriate.