The following description of how autism is diagnosed in children and young people in the UK is taken from 'Autism diagnosis in children and young people: Recognition, referral and diagnosis of children and young people on the autism spectrum' (2011). London: National Institute for Health and Clinical Excellence, pp. 241-242.
a) There is wide variation in rates of identification and referral for diagnostic assessment, waiting times for diagnosis, models of multiprofessional working, assessment criteria, diagnostic practice, and biomedical investigation and genetic counselling for children and young people with features of ASD. These factors contribute to delays in reaching a diagnosis and subsequent access to appropriate services.
b) Healthcare professionals usually make the diagnosis of ASD in a child or young person. By working jointly with social care and educational professionals in a range of environments, healthcare professionals share information regarding the diagnosis and agree on a plan for future support and/or interventions for each child or young person. When the process works well, professionals and carers communicate right from the start, laying the foundation for a long-term understanding between children, carers and the professionals supporting their needs. However, practice varies and in some parts of the country waiting lists for multiprofessional specialist assessment are longer than 2 years.
c) Diagnosis is a process that can have a variable time frame involving different competencies amongst the professionals involved. However, flexibility in approach to diagnosis is not always a feature of current diagnostic assessment in the NHS.
d) The current use of biomedical investigations to rule out other conditions and thresholds for genetic counselling referral varies markedly. Opinion also varies on the value of biomedical investigations in the diagnostic assessment of autism and coexisting conditions.
e) Children and young people with other existing conditions featuring intellectual, physical or sensory disability and/or mental health problems may not be recognised as having symptoms of ASD, and there may be overlaps between a developmental disorder and a coexisting condition. Children's social circumstances (for instance, 'looked after' children) may also affect how quickly features of ASD are recognised.
f) Some of the behaviours that define ASD may also feature in other communication disorders and learning disabilities (such as childhood attachment disorders), as well as being the result of other conditions (such as epilepsy or acquired brain injury) or childhood experiences (such as trauma or maltreatment). Children and young people may be wrongly diagnosed as having a mental illness when they have features of ASD, or, conversely, they may be misdiagnosed with autism when they have another condition. Misdiagnosis can lead to delays in children and young people receiving the care and support that they need.
g) The process and content of information-sharing varies widely, for instance in the provision of information and support for the family while awaiting diagnosis and immediately after.
h) Clinical guidance for diagnosis has been published for the NHS in Scotland, 'Assessment, diagnosis and clinical interventions for children and young people with autism spectrum disorders' (Scottish Intercollegiate Guidelines Network [SIGN 98] 2007). The National Service Framework for Children, Young People and Maternity Services (2004) included an 'Autism exemplar', which described the 'patient journey' of a 3-year-old boy with ASD and built on guidance in the National Autism Plan for Children (NAP-C). The Autistic Spectrum Disorder Strategic Action Plan for Wales (2008) focused on the role of strategic health plans to develop services and interagency cooperation between health and education for children and young people with ASD. The Department of Health published the consultation document 'A better future' (2009) on designing services to improve support for adults with autistic spectrum conditions. The National Audit Office is currently undertaking a study, 'Supporting people with autism through adulthood' focusing particularly on the transition from adolescence to adulthood.
i) This guideline is needed to make services more child and family/supporter centred and to help reduce variation in professional practice by improving initial recognition of the features of ASD and the timing and process of diagnostic assessment to enable longer-term future care.