Table 1 Indicators of the need for assessment

It is good practice for professionals working with autistic individuals to be aware of the core features of autism, including more subtle manifestations of symptoms in individuals with average or above average intellectual functioning

The presence or observation of any of the following could prompt further investigation, including a referral for a diagnostic assessment; adapted from the DSM-5 TR diagnostic criteria and ICD-11:

 • Difficulties with social interaction with staff or peers, including initiation and engagement in to-and-fro conversations, reduced sharing of interests or emotions, and difficulty responding appropriately, including selective/situational mutism

 • Reduced, unusual or poorly integrated non-verbal communication, such as eye contact, facial expression or understanding/use of gestures

 • Difficulties developing and maintaining relationships with staff and peers, including adjusting behaviour for varying social contexts

 • Insistence on sameness and inflexible adherence to routines, such as extreme reactions or distress  to minor changes in their routine or environment and cognitive rigidity

 • Unusually intense preoccupations with subjects or objects and/or circumscribed interests that are excessive and may impact on communication or functioning

 • Stereotyped or repetitive motor movements, use of objects or speech, such as repeating the words or phrases of others (echolalia) or using stereotyped or idiosyncratic language

 • Unusual sensory interests or sensory sensitivities, such as hyper and hypo sensitivity and/or sensory avoidance/seeking

 • The presence of other neurodevelopmental conditions, such as ADHD and intellectual disability

 • A family history of neurodevelopmental and/or genetic conditions with known associations with autism

 • An existing diagnosis of OCD or the presence of obsessive/compulsive traits

 • Existing diagnoses of personality disorder, particularly schizoid personality disorder, obsessive–compulsive personality disorder and/or personality disorder – not otherwise specified

 • Highly detailed offence accounts combined with indicators of poor episodic memory and/or sequencing difficulties