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At the heart of general practice since 1960

August 2007: Early identification key in autism spectrum disorders

How are autism spectrum disorders diagnosed?

What are the developmental warning signs?

What evidence-based interventions are available?

How are autism spectrum disorders diagnosed?

What are the developmental warning signs?

What evidence-based interventions are available?

Autism spectrum disorders (ASD) is the current term used to describe a group of complex neurodevelopmental disorders that includes autism, atypical autism and Asperger syndrome. Recent studies have reported increased rates of ASD, which are now thought to result from improved recognition and diagnosis rather than environmental factors.1 While autism is traditionally considered to be associated with learning disabilities, it is now recognised that around 50% of children and young people with ASD have normal intellectual functioning.2

At the core of the diagnostic concept of ASD is a triad of impairment:3,4

• Social impairment: delayed or atypical social, interpersonal development

• Impairment of language and communication: impaired verbal

and non-verbal communication

• Impaired thinking and behaviour: rigidity of thought and behaviour; repetitive, ritualised behaviour; impoverished imaginative play.

Primary care has an important role to play in the early recognition of ASD.5-7 However, the highly variable initial presentation of ASD presents difficulties, and requires healthcare professionals to have a high index of suspicion and consider ASD in the differential diagnosis of any child with features suggestive of abnormal development, or in the absence of normal developmental features.

To support healthcare professionals in this area of work, SIGN has recently produced an evidence-based guideline on the assessment, diagnosis and management of ASD in children and young people (SIGN 98).7

Recognising ASD

It is important to recognise ASD as early as possible, to allow young children to benefit from early intervention programmes. Secondary screening can help in the early identification of ASD in children at increased risk, such as those with a family history of ASD, a genetic syndrome or in children with developmental, emotional and behavioural problems.7 Before two years of age children show developmental features that are non-specific to ASD; however, by the time the child reaches 2-3 years healthcare professionals can reliably recognise typical features of ASD.8,9

Parents or other family members are often the first to recognise that their child seems to be different from siblings or other children. This can be something concrete, such as delayed language development or an apparent hearing deficit, or it can be more subtle, such as a lack of interest in playing with other children. Whatever the presenting difficulty, it is essential that healthcare professionals investigate further and rule out ASD by enquiring about other features suggestive of ASD and other developmental disorders.

Two instruments are of potential use for healthcare professionals involved in identifying ASD in young children, either in response to parents' concerns or as part of child health surveillance. The Checklist for Autism in Toddlers (CHAT)10,11 and modified CHAT (M-CHAT)12 are both designed for use with children in the 18-24 months age range. While identifying ASD depends on using clinical skills and knowledge to identify abnormal patterns of development, these instruments can provide a structured format for asking questions about features suggestive of ASD. The four case studies, attached, are examples of ASD in children of different ages. Tables 1, 2, 3 and 4, attached, provide an outline of features suggestive of ASD in different age groups.

Where there are features suggestive of ASD, the child or young person should be referred to the appropriate service for specialist assessment. There are often significant differences in services between regions. However, all services should strive to provide a multidisciplinary team to carry out reliable and comprehensive diagnostic assessments.

Conditions associated with ASD

An important aspect of the care and support that GPs can provide to children and young people with ASD is in identifying and managing physical and mental health problems. This can have a positive impact on long-term outcome. The communication and developmental impairment associated with ASD can create difficulties for health professionals in recognising and assessing these physical and mental health problems.

Since they occur more commonly, there are some health problems that should be ruled out in all children and young people with ASD. They include: hearing and visual impairments; sleep problems; mental ill health, particularly attention deficit hyperactivity disorder (ADHD), anxiety and depression and epilepsy.7

Clinical interventions

The recently published SIGN guideline recognises that there is little robust evidence to support many of the interventions reported as effective for children and young people with ASD. For some interventions this reflects a lack of evidence, because appropriate studies have never been carried out; but for other interventions currently in use there is evidence of a lack of effect.

The general lack of evidence on the effectiveness of interventions creates difficulties for families and healthcare professionals when considering which interventions may be of some help. Healthcare professionals can help parents and families to consider the costs and benefits of potential interventions, in the light of available evidence where appropriate.

Non-pharmacological interventions

Early interventions aimed at improving functioning and outcomes are now viewed as an accepted part of the management of ASD in children and young people.

Some intervention models focus on specific developmental domains, such as communication or social functioning, while others have a broader focus on improving overall functioning. The SIGN guideline found relatively little robust evidence to support one programme over another, but recognised the emerging evidence to support the use of communication and behavioural interventions and the importance of involving families in intervention programmes.7

There is widespread interest in the effectiveness of biomedical and nutritional interventions, such as vitamin supplementation or casein and gluten exclusion diets. At present, there is insufficient published evidence to be able to make a statement about the effectiveness of such interventions.

Some children and young people with ASD exhibit significant food selectivity or abnormal eating patterns, and a dietitian's advice and support should be sought to ensure that their nutritional needs are met.

Pharmacological interventions

There is a general lack of evidence to support the use of medication in children and young people with ASD. No medication has been shown to have an impact on the core features of ASD, and none are currently licensed specifically for use in ASD.

There is some evidence to support the use of medication in the treatment of conditions often associated with ASD, such as problem behaviour, ADHD or sleep disorders. However, the use of these ‘off-licence' medications must be monitored and assessed by specialist services as part of a comprehensive package of interventions.

Information and support for parents and families

Parents and families experience significant anxiety during the process of assessment and diagnosis. Information, both verbal and written, is therefore an important component of service provision.

Useful information

Further information on useful resources for children and young people with ASD, parents and families and health professionals is given in SIGN 98

NHS Education for Scotland provides a learning resource website on autism spectrum disorders


Dr Iain McClure
consultant child and adolescent psychiatrist, Murray Royal Hospital, Perth. Chair of the SIGN 98 guideline development group

Dr Craig A Melville
senior lecturer in learning disabilities psychiatry, University of Glasgow, Gartnavel Royal Hospital. Member of the SIGN 98 guideline development group

Key points Case study 1 Case study 2 Case study 3 Case study 4 General developmental warning signs of possible ASD in pre-school children Table 1: General developmental warning signs of possible ASD in pre-school children Warning signs of possible ASD in school-age children Table 2: Warning signs of possible ASD in school-age children Additional warning signs of possible ASD in adolescents Table 3: Additional warning signs of possible ASD Additional warning signs of possible ASD

in adolescents Table 4: Extract from a checklist for provision of services and information

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