NICE has issued three clinical guidelines on autism, one on its diagnosis and management in adults (CG142), and two relating to autism in children and teenagers. These cover recognition, referral and diagnosis (CG128), and support and management (CG170). Guidelines were updated in 2017 and 2021.2,3,17

For children, diagnosis considers the nature of aspects such as:2
·       spoken language
·       response to other people
·       interactions
·       eye contact, pointing and other gestures
·       ideas and imagination
·       unusual or restricted interests and/or rigid and repetitive behaviours.

As the child ages, other factors may also be considered, such as having an unusual profile of skills or deficits, as well as the degree of age-appropriate maturity, naivety, or independence.
For adults, a comprehensive assessment should involve a family member, partner or carer. Documentary evidence such as school reports may shed some light on past behaviour. Depending on whether any learning disability is present, a range of assessment tools is available, such as the Autism-Spectrum Quotient 10 items (AQ-10) tool.3
Autistic people may display behaviour that challenges, resulting from their interaction with environmental factors. This can include stereotypic behaviour (such as rocking or hand flapping), anger, aggression, self-injury, and disruptive or destructive behaviour. NICE says such behaviour is seen as challenging when it affects the person’s or other people’s quality of life and/or jeopardises their safety.