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Autism spectrum disorder – screening, diagnosis and intervention

Overview of ASD

Autism spectrum disorder (ASD) is the collective term for a group of neurodevelopmental disorders characterised by:^26,28

early onset impairments in social communication and interaction, and
restricted or repetitive interests or behaviours.

ASD includes a variety of disorders that were previously known as autistic disorder, Asperger’s disorder and pervasive developmental disorder not otherwise specified.^16,25 However, under the revised DSM-5 and ICD-11, all of these disorders are now classified as autism spectrum disorder. Individual clinical characteristics are then noted through the use of specifiers, eg:^1,12

with or without accompanying intellectual impairment
with or without language impairment
associated with a known medical/genetic or environmental/acquired condition
associated with another neurodevelopmental, mental or behavioural disorder.

For example, individuals previously diagnosed with Asperger’s disorder would now receive a diagnosis of ASD without language or intellectual impairment.¹

World-wide prevalence of ASD is reported to be 1-1.5%.²⁸ In Australia, current estimates indicate between 1 in 70 and 1 in 150 children are affected by ASD, with males four times as likely as females to be diagnosed.^2,5 The number of people diagnosed with ASD in Australia has also increased considerably in recent years. It is not known whether the prevalence is actually increasing, or whether this is an apparent increase due to higher levels of diagnosis based on broader awareness.²

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Causes and prognosis of ASD

The precise cause of ASD is not known, although research indicates that genetic factors are important. Other risk factors include:²¹

advanced paternal and/or maternal reproductive age
gestational factors, such as complications during pregnancy and exposure to chemicals.

Vaccinations, the components of vaccines (thimerosal or mercury), or multiple vaccines (eg the measles, mumps and rubella vaccine) are NOT associated with the development of ASD.^8,9

Prognosis depends on many factors and is difficult to accurately predict in early childhood, especially in children younger than 3 years old.⁸ While early intervention has been shown to improve outcomes for children with ASD,¹⁵ there are a number of indicators that can help to distinguish which children will have a better long term prognosis. Click on the boxes below for these indicators.

Indicators of better prognosis

These include:⁸

higher childhood intelligence
communicative phrase speech before age 6
normal nonverbal skills by age 3 years
fewer childhood social impairments.

Indicators of poorer prognosis

These include:⁸

severe ASD symptoms, ie

lack of joint/shared attention by age 4 years (ie not holding up or pointing to objects to involve another person in the experience or not participating in a shared activity, eg book reading)
lack of functional speech by age 5 years

intellectual disability
seizures, especially if onset during adolescence
comorbid medical or psychiatric disorders.

Signs and symptoms of ASD

Due to the nature of the disorder, signs and symptoms of ASD vary between individuals.

Symptoms begin to emerge during the first two years of life and diagnosis is usually clear by 30–36 months, especially in children at the more severe end of the spectrum. However, symptoms in some individuals with less severe variants may not be recognised until they are at pre- or primary school, when their social difficulties and rigid, odd or repetitive behaviours become more noticeable and problematic.²⁵

Signs and symptoms of ASD may overlap with other neurodevelopmental disorders and intellectual disabilities, so for a diagnosis to be made, the child needs to demonstrate difficulties in both social communication and interaction as well as demonstrating restricted, repetitive behaviours and/or interests. Click on the boxes below for information about common signs of difficulties in these areas. Also see the resource section of this activity for more information on the signs and symptoms of ASD.

Red flags: Communication

Signs that a child might have ASD include:^17,10,22

not babbling, cooing or gesturing (pointing, waving, grasping) by 12 months of age
not saying single words by 16 months of age
not saying two-word phrases on their own (rather than just repeating what someone else says (echolalia)) by 24 months of age
not consistently responding to their name
not sharing interests or achievements with others (eg pointing to a dog and seeing if the other person has seen it too)
not using facial expressions to communicate
not engaging in imaginative play
having any loss of a language or social skill at any age.

Red flags: Behaviour

Behavioural signs that a child might have ASD include:¹⁸

having very narrow and intense interests
having restricted eating patterns
insisting on routine, and having difficulties coping with change
having difficulty organising and planning ahead
repeating body movements or displaying unusual body movements (eg back-arching, hand-flapping, arm-stiffening and walking on toes)
showing signs of sensory sensitivities (eg not liking labels on clothes, sound sensitivity or licking or sniffing objects).

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Assessment and screening process

As a GP, parents or maternal and child health nurses will typically contact you when they suspect or identify a developmental delay in a child. However, you also play a key surveillance role in identifying young children who might require further screening and referral for an ASD assessment.²⁵

When signs and symptoms that could be caused by ASD are identified or suspected, further exploration is essential, both to rule out other possible conditions and to confirm ASD as a possible diagnosis. Early diagnosis leads to earlier access to interventions, and this has been shown to improve function and reduce societal costs long term.^6,28

Clinical assessment should incorporate a:⁸

history of current and past behaviours with a focus on eliciting core features of ASD and other common symptoms
full medical history, including family and social history
physical examination to rule out other conditions (eg impaired hearing or other sensory impairment, metabolic, gastrointestinal or other neurological conditions).

There is no single test to screen for ASD, and a large number of screening tools are available. The Modified Checklist for Autism in Toddlers - revised (M-CHAT-R) has been validated as a parent-administered screening tool for toddlers between 16-30 months and the Autism Research Centre (UK) provides links to downloadable tests for children, adolescents and adults. To save time in a consultation, you might ask parents to complete a screening tool at home and bring it to the appointment.

A positive screen for ASD using one of these screening tools is not diagnostic. It is therefore important to refer the child to a specialist multi-disciplinary team, paediatrician, psychiatrist or clinical psychologist experienced in the assessment of pervasive developmental disorders for a formal diagnosis. These diagnostic services can be either public or privately run, though many publicly funded services have long waiting lists.^4,13 See the resources section for links to these services.

Diagnostic process

To diagnose ASD, the assessing individual or team may:³

take a family history and ask about the child’s developmental history
conduct semi-structured interviews (eg the Autism Diagnostic Interview - Revised (ADI-R) or Diagnostic Interview for Social and Communications Disorders (DISCO))
spend time with the child assessing their communication skills
use a play-based assessment tool with the child such as the Autism Diagnostic Observation Schedule (ADOS).

To confirm a diagnosis of ASD, the assessing individual/team will refer to the signs and symptoms of ASD in the DSM-5 and identify how many of these symptoms are present in the child.^16,19

If the child is diagnosed with ASD, they will also be given a severity ranking (levels 1-3) for each of the two areas of difficulty.¹⁶ These rankings can be used to understand how much support the child will need and can also affect the amount of government funding the child might receive.^16,20

Comorbid conditions may also be diagnosed before, during or after the assessment process. These will also need to be managed to ensure the best quality of life for the child.^16,28 Click on the boxes below to reveal some common comorbid conditions and physical health issues.

Comorbid conditions

Comorbid conditions can include:⁸

developmental conditions, eg intellectual disability, tic disorders and motor abnormalities
attention deficit hyperactivity disorder (ADHD)
mental health conditions, eg depression and anxiety disorders, including obsessive compulsive disorder
medical conditions, including genetic disorders such as fragile X, Rett syndrome, tuberous sclerosis, Down syndrome and phenylketonuria (PKU).

Physical health issues

These can include:^20,17

gastrointestinal disorders
seizure disorders
nutritional deficiencies related to a restricted diet (due to tendency in some children to have strong dislikes for particular foods or food groups due to texture, smell, taste, etc.)
behavioural and/or emotional tendencies such as difficulty regulating emotions, sleep problems and self-injurious behaviour.

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Common ASD interventions

Early intervention is critical in any child suspected of having ASD to enable them to reach their full potential.

With a large number of interventions and ASD treatment options available, GPs play an important role in supporting parents and carers who may be overwhelmed and risk being tempted by non-evidence based interventions and claims of treatments that can ‘cure’ ASD.

There is no ‘cure’ or medication available to treat ASD (though medication may be indicated to treat common comorbidities such as mental health issues and ADHD);^21,25 however, a lot of research has been done into the outcomes of ASD interventions/treatments.

In general, this research has shown that high intensity interventions which address the child and family’s needs using behavioural, educational and/or developmental approaches are the best of the currently available early interventions. There have been consistently good outcomes for intensive applied behavioural analysis (ABA) programs and there is growing evidence that intensive developmental and combined interventions are also effective.¹⁵

Click on the buttons below to learn more about some the different interventions available. Also see the resource section of this activity for more comprehensive information for GPs and parents on the range of ASD interventions.

Behavioural interventions

Behavioural interventions are grounded in learning theories such as applied behavioural analysis (ABA) and focus on teaching children new behaviours and skills using a variety of specialised, structured techniques.^14,21 They are the best supported by evidence and research, and therefore are the most commonly used type of intervention.²¹

Behavioural intervention techniques are not typically delivered as stand-alone interventions, but are combined and individualised to the needs of the person with ASD. Examples of behavioural interventions include:

positive reinforcement
prompting and prompt fading
imitation training
discrete trial teaching (DTT)
incidental teaching
task analysis
video and in vivo modelling
self-management
pivotal response treatment (PRT)
positive behaviour support (PBS).

Early intensive behavioural intervention (EIBI) is a comprehensive and individualised treatment approach for young children, and typically involves many of the techniques noted above. EIBI should begin early (as soon as a diagnosis is suspected or confirmed), be intensive (20 hours per week of individualised intervention addressing skills in multiple developmental areas), and include parents and carers.

Developmental interventions

Developmental interventions aim to help children form positive, meaningful relationships with other people by teaching them social and communication skills in everyday, structured settings. They also aim to help children develop skills for daily living.²¹

Examples of developmental-based interventions include:²¹

the developmental social-pragmatic (DSP) model
DIR®/Floortime®
Relationship Development Intervention® (RDI®)
responsive teaching.

Studies on some of these interventions have shown potentially positive results, though more research is needed.²¹

Combined interventions

These interventions combine elements of behavioural and developmental methods and focus on working with and managing the characteristics of ASD.^15,21

Examples of combined interventions include:²¹

early start Denver model (ESDM)
SCERTS® model
TEACCH (Treatment and education of autistic and related communication-handicapped children).

Family-based interventions

Family-based interventions emphasise the idea that family involvement in therapy is central to meeting the child’s developmental needs. These interventions allow parents to drive decision-making regarding the strategies taught and require families to take a key role in delivering them. They also provide guidance, training, information and support to family members to do so.²¹

Research on family-based interventions is limited but growing. The success of these interventions depends on having strong and collaborative parent-professional relationships. Their effectiveness also relies on addressing the needs of the whole family, so that everyone in the family benefits, not just the child with ASD.²¹

An example of a family-based intervention is the More Than Words® program.²¹

Other interventions

Targeted therapies are often used together with, or as part of, the previously discussed interventions/programs. For example, using speech therapy to develop a child’s communication and social skills and/or occupational therapy to develop skills for daily life, including physical skills.²¹

There are also a range of other interventions that sit outside the above categories. These generally aren’t supported by scientific evidence, with considerable evidence showing no effect at all for some (eg secretin); and potential risks associated with others (eg withholding the MMR vaccine).²¹ Examples of other non-evidence based interventions include:²¹

music therapy
chelation
elimination diets
yeast overgrowth management
sensory integration therapy.

A common concern about these types of therapies, even those that do no direct harm, is that they use time, energy and sometimes money that families could otherwise spend on well-established and well-supported therapies.²¹

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Providing support and guidance to parents

With such an extensive range of interventions available, parents can feel overwhelmed trying to identify the best ASD intervention or program for their child and may come to you for advice. GPs therefore need to be prepared to support and educate parents in this matter.

GPs also play an important role in caring for the mental and physical health of parents and carers. Caring for a child with ASD can be emotionally exhausting, so it is important to regularly check in with parents to see how they are coping and to ensure that they are getting the support and respite they need to protect their wellbeing.

When offering advice on ASD interventions/programs, it is important to remember that no single intervention will suit all children and their families.¹⁷ GPs should therefore encourage parents to examine a range of different aspects of each intervention/program before making their decision. These are listed below. Click on each box below for more information.

Basis of the intervention

Some interventions are based on flawed theories of what causes ASD, and others can claim to 'cure' ASD, despite the fact that ASD is not an illness or a disease.²² So you should encourage parents to look for an intervention that is based on scientific evidence.^15,22

Evidence-based interventions provide assurances that they have been assessed for both benefits and risks. However, it is also important to remember that evidence in favour of an intervention does not guarantee that it works with every person with ASD, but it does provide some reassurance to people who are thinking about using it.²²

Individual variation

Each person with ASD is different, with strengths and needs in different areas, as well as experiencing a range of differing associated features. These strengths/needs would have been identified during the initial diagnostic assessment and should be used to inform the individual program. Parents should therefore be encouraged to look for an intervention where the provider will create an individual plan/program that is based on the strengths and needs of the child.^14,15,17,22

The plan should also focus on the ‘whole child’, rather than just a single area of functioning. Generally, this will be best achieved when the plan is developed and delivered by a collaborative, multidisciplinary team. This team may consist of a number of professionals including educators, speech pathologists, occupational therapists, psychologists, and/or board certified behaviour analysts, who provide collaborative assessments, jointly set goals, provide interventions and review progress.^14,15

Parents should also be advised to look for a provider who will regularly review, evaluate and adjust the individual’s plan to ensure it continues to meet the needs of the child.¹⁵

Family involvement

ASD adds additional stress to families and an effective program should be sensitive to this.¹⁵

Family members are in the best position to identify the strengths and needs of the child and continue to implement strategies taught as part of intervention programs at home and in the community.¹⁵

GPs should therefore encourage parents to look for an intervention that:^15,17

includes family members when creating, reviewing and updating the individual intervention plan
supports and guides family members to help them implement strategies at home
provides support and respite to parents to ensure that they are looking after their own mental and physical health.

Professionals delivering the training

To ensure that the intervention is delivered effectively, the professionals involved in delivering it must have the appropriate training and qualifications.²² The professionals should also be able to demonstrate that they have an appropriate level of experience, ie they have previously worked successfully with people with ASD.^15,22

It is also equally important that they have the right attitude, that is they:²²

understand ASD and the differences that are present in people on the spectrum
understand the strengths and needs of the person they are working with
don’t make assumptions about the people they care for
always respect the person's feelings and views.

Staffing ratios, especially in group interventions should also be considered. Implementation of individual goals in a small group context is not feasible with less than two adults for six children.¹⁵

Amount, intensity and duration: Fifteen to twenty-five hours per week is generally recommended for early ASD interventions. You should encourage parents to consider not just the number of hours but the quality of those hours. Furthermore, while the characteristics of ASD are lifelong, the need for support varies among individuals and according to their age and stage. Intensity, timing and duration of the intervention should therefore be adjusted according to the individual’s needs.^15,17

Cost

Some interventions can be extremely expensive and may or may not be fully covered by government funding, so this can be an important consideration for parents when choosing an intervention/program.^15,11

While many children will be able to access funding through the NDIS, at the time of writing, the NDIS has not been rolled out Australia-wide. If it is not yet available in your area, funding may be available through the Helping Children with Autism (HCWA) program. Medicare also provides rebates for diagnosis, contribution to treatment plans and treatment services for certain individuals.⁷

Shows benefits

Interventions should provide significant benefits to the individual with ASD.²² GPs should encourage parents to ask the provider to outline the expected benefits and outcomes for their child, and if possible provide any evidence of improvements based on a significant size study population.

While everyone’s views on what counts as a significant benefit varies; if the child has not made any significant progress after participating in the program for a reasonable period of time, GPs should encourage the parents to consider looking into a different intervention.²²

If you would like to do a short case study on this topic, you can enrol in the Autism spectrum disorder – screening, diagnosis and intervention activity on gplearning.

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Additional resources

General information

Autism Awareness Australia: Autism signs across the lifespan
Autism Behavioural Intervention Association: GP Information Kit
Autism CRC: A National Guideline for the Assessment and Diagnosis of Autism Spectrum Disorder in Australia.
Autism CRC: Knowledge Centre
Department of Health: Medicare items supporting early diagnosis and treatment
Royal College of General Practitioners (UK): Autism Spectrum Disorders Clinical Toolkit

Screening tests

Autism Research Centre provides links to downloadable tests for children, adolescents and adults
Modified Checklist for Autism in Toddlers (M-CHAT-R/F) – validated for toddlers between 16-30 months

ASD interventions

The Association for Science in Autism Treatment (ASAT) maintains a list of all marketed autism interventions. Currently, there are over 500 distinct marketed interventions for autism, the vast majority of which lack any scientific support. ASAT has a section on their website specifically for medical practitioners to help GPs stay up to date with the latest research in autism
Raising Children Network (Australia). Types of interventions for children with autism spectrum disorder. Raising Children Network, 2017.
Prior M, Roberts JM, Rodger S, Williams K. A Review of the Research to Identify the Most Effective Models of Practice in Early Intervention for Children with Autism Spectrum Disorders. Canberra: Australian Autism Research Collaboration (AARC) for Australian Government Department of Families, Housing, Community Services and Indigenous Affairs, Australia, 2011.
Autism Behavioural Intervention Association: Resources

ASD diagnostic services

Information for parents

Raising Children Network: Children with autism spectrum disorder
Autism Awareness Australia
Autism Awareness Australia: Medicare rebates for diagnosis and treatment
Autism Behavioural Intervention Association: Parent Information Kit
Association for Science in Autism Treatment (ASAT)

State-based ASD associations

Australian Capital Territory: Marymead Autism Centre
New South Wales:

Northern Territory: Autism NT
Queensland: Autism Queensland
South Australia: Autism SA
Tasmania: Autism Tasmania
Victoria: Amaze (previously Autism Victoria)
Western Australia: Autism Association of Western Australia

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References

American Psychiatric Association. Diagnostic and statistical manual of mental disorders, 5th edn (DSM-5). Arlington, VA: American Psychiatric Association, 2013.
Australian Institute of Health and Welfare. Autism in Australia. Canberra: AIHW, 2017.
Autism Awareness Australia. Understanding the assessment process. Autism Awareness Australia, 2019. [Accessed July 2019]
Autism Awareness Australia. Who can diagnose. Autism Awareness Australia, 2019. [Accessed July 2019]
Autism Spectrum Australia. Autism prevalence rates up by an estimated 40% to 1 in 70 people. Autism Spectrum Australia, 2018.
Brasic JR, Farhadi F. Autism spectrum disorder. Medscape, 2018. [Accessed July 2019]
Department of Health. Autism – Helping children with autism program: Medicare items supporting early diagnosis and treatment. Canberra: Department of Health, 2014. [Accessed August 2019].
DynaMed Plus [Internet]. Autism spectrum disorders. Record No. T113665. Ipswich (MA): EBSCO Information Services. 1995 - . [updated December 2018] [Accessed July 2019]
Lai MC, Lombardo MV, Baron-Cohen S. Autism. Lancet 2014;383(9920):896-910.
Lord C, Elsabbagh M, Baird G, Veenstra-Vanderweele J. Autism spectrum disorder. Lancet, 2018 392(10146):508-520.
Morales DR, Slattery J, Evans S, Kurz X. Antidepressant use during pregnancy and risk of autism spectrum disorder and attention deficient hyperactivity disorder: systematic review of observational studies and methodological considerations. BMC Med, 2016; 16(1):6.
National Disability Insurance Agency. Children to get faster access to NDIS supports. Canberra, NDIS, 2019.
Parliament of Victoria, Family and Community Development Committee. Inquiry into services for people with Autism Spectrum Disorder. Final Report. Melbourne, Parliament of Victoria, 2017.
Prior M, Roberts JM, Rodger S, Williams K. A Review of the Research to Identify the Most Effective Models of Practice in Early Intervention for Children with Autism Spectrum Disorders. Canberra: Australian Autism Research Collaboration (AARC) for Australian Government Department of Families, Housing, Community Services and Indigenous Affairs, Australia, 2011.
Prior M, Roberts JM. Early Interventions for Children with Autism Spectrum Disorders: Guidelines for Good Practice, 2012. Canberra: Department of Social Services, 2012.
Raising Children Network (Australia). DSM-5: autism spectrum disorder diagnosis. Raising Children Network, 2018. [Accessed July 2019]
Raising Children Network (Australia). Early interventions for children with autism spectrum disorder: getting started. Raising Children Network, 2017. [Accessed July 2019]
Raising Children Network (Australia). Early signs of autism spectrum disorder. Raising Children Network, 2018. [Accessed August 2019]
Raising Children Network (Australia). How autism spectrum is diagnosed. Raising Children Network (Australia), 2018. [Accessed July 2019]
Raising Children Network (Australia). The National Disability Insurance Scheme and HCWA: FAQs. Raising Children Network, 2017. [Accessed July 2019]
Raising Children Network (Australia). Types of interventions for children with autism spectrum disorder. Raising Children Network, 2017. [Accessed July 2019]
Research Autism. Principles for Autism Interventions. London: Research Autism, 2018. [Accessed July 2019]
Research Autism. Secretin and Autism. London: Research Autism, 2018. [Accessed July 2019]
Steinhausen HC, Mohr Jensen C, Lauritsen MB. A systematic review and meta-analysis of the long-term overall outcome of autism spectrum disorders in adolescence and adulthood. Acta Psychiatr Scand 2016;133(6):445-52.
Tonge B, Brereton A. Autism spectrum disorders. AFP 2011;40(9):672-677.
Whitehouse AJ, Evans K, Eapen V et al. The diagnostic process for children, adolescents and adults referred for assessment of autism spectrum disorder in Australia: A national guideline (draft version for community consultation). Autism CRC, 2017.
World Health Organization. International Classification of Diseases for Mortality and Morbidity Statistics, 11^th edn (ICD-11). 6A02 Autism spectrum disorder. Geneva WHO, 2019. [Accessed July 2019]
Zwaigenbaum L, Penner M. Autism spectrum disorder: advances in diagnosis and evaluation. BMJ 2018;361:k1674.

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