Autism Diagnostic Guideline for Adults

This is the referral pathway for autism diagnosis of adults in Plymouth who do not meet the Learning Disability Services criteria.

People with an autism diagnosis who need treatment for a comorbidity should be referred to the appropriate service for that comorbidity, that service should make reasonable adjustments.

Autism is a lifelong neurodevelopmental condition, the core features of which are persistent difficulties in social interaction and communication and the presence of stereotypic (rigid and repetitive) behaviours, resistance to change or restricted interests. The way that autism is expressed in individual people differs:

  • At different stages of life
  • In response to interventions
  • With the presence of coexisting conditions such as learning disabilities (also called 'intellectual disabilities')

People with autism also commonly experience difficulty with cognitive and behavioural flexibility, altered sensory sensitivity, sensory processing difficulties and emotional regulation difficulties. The features of autism may range from mild to severe and may fluctuate over time or in response to changes in circumstances.

Over recent years there has been increasing recognition of the needs of people with autism spectrum condition (ASC). The Autism Act (2009) has laid down in statute the requirements to address these needs. More recently NICE guidance has been published for adults with ASC (NICE, 2012), outlining best practice in recognition, assessment and management for adults with autism.

The prevalence of autism in the UK population is estimated at 157 per 10000 populations (or 1.6%) (Baron-Cohen 2009). Estimates suggest that up to 80% of those with ASC do not have learning disabilities (Elsabbagh et al. 2012). From these figures it is estimated that 2,700 people living in Plymouth have ASC. The number of adults with a diagnosis of ASC in Plymouth is unknown but there are likely to be large numbers of people who have not yet been assessed or diagnosed.


Signs and Symptoms

Consider assessment for possible autism when a person has:

One or more of the following:

  • Persistent difficulties in social interaction
  • Persistent difficulties in social communication
  • Stereotypic (rigid and repetitive) behaviours, resistance to change or restricted interests
  • Problems in obtaining or sustaining employment or education
  • Difficulties in initiating or sustaining social relationships
  • Altered sensory sensitivity, sensory processing difficulties
  • Emotional dysregulation

History and Examination

  • Evidence of abnormalities in early development (including social interactions, social communication, lack of imaginative play, restricted, repetitive interest pattern)
  • A history of a neurodevelopmental condition (including learning disabilities and attention deficit hyperactivity disorder) or mental disorder
  • Family history of Autism or other neurodevelopmental disorders

Differential Diagnoses

  • Learning Disabilities
  • Attention deficit hyperactivity disorder (ADHD)

Red Flags

  • If presenting with acute comorbid mental health issue follow normal referral pathway into mental health or learning disability services
  • If presenting with urgent social care needs contact Adult Social Care


For adults with possible autism who do not have a moderate or severe learning disability, consider using the Autism-Spectrum Quotient – 10 items (AQ-10)[1]. (If a person has reading difficulties, read out the AQ-10.)


Referral for the diagnosis of autism is to Community Mental Health Teams

Adults with learning disabilities should be referred to the Community Learning Disabilities Team for a comprehensive assessment (all adults with a learning disability should be Read coded – if there is uncertainty about the presence of learning disabilities the Community Learning Disabilities Team should be contacted)

Referral Criteria

  • Autism is suspected based on clinical judgement (taking into account any past history provided by an informant)
  • Or score of 6 or above on AQ-10

Referral Instructions

  • Referral to be made via DRSS. Please include the evidence that suggests the presence of Autism and AQ-10 if completed

Refer via e-Referral system:

  • Specialty: Mental Health - Adults of all ages
  • Clinic Type: Not Otherwise Specified
  • Service: DRSS-Western-Mental Health-Adult-NEW Devon CCG-99P

Supporting Information

Individuals who have a diagnosis of Autism and their carer's are entitled to a social care assessment; however they will only be eligible for services if they have eligible needs.

Long-term Condition Self-Management Programme

GPs and patients can refer to Improving Lives Plymouth for patient support with any long-term physical or low level mental health condition. The service helps people to better manage their condition and to achieve a better quality of life.

Patient Information

Plymouth Online Directory

RCPsych Autism Information

National Autistic Society

NHS Choices - Autism in adults


NICE guidance (CG142)

Pathway Group

This guideline has been signed off by the Western Locality on behalf of NEW Devon CCG.

Publication date: August 2015
Updated: October 2018


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