Autism Spectrum Disorder (ASD)

Autism Spectrum Disorder (ASD)

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Autism spectrum disorder (ASD) is a neuro-developmental disorder characterised by abnormal social interaction, communication and restricted, repetitive behaviours. ASD is four times more prevalent in boys than girls. In the UK, 1 in 100 people are considered to be on the autistic spectrum.

There are other names used for ASD such as childhood autism or Asperger syndrome. Asperger syndrome is now referred to as autism spectrum disorder; however, it is characterised by the absence of intellectual impairment and/or impairment of functional language.


In most cases, there is no identifiable cause for ASD however there are a few known, predisposing medical conditions. These include:

  • Infantile spasms
  • Congenital rubella
  • Tuberous sclerosis
  • Fragile X syndrome

Risk factors

Risk factors for ASD include:

  • Male sex
  • Family history
  • Genetic variants such as PTEN, MeCP and several submicroscopic copy number variants (CNV)
  • Chromosomal abnormalities

Clinical features

Typical features of ASD can be classed into three categories: social interaction, communication and restricted, repetitive behaviours.

Social interaction

Patient's may exhibit the following social features:

  • Lack of response to other people's emotions
  • Unable to interpret social cues
  • Inability to form social attachments


Patient's may exhibit the following communication features:

  • Usually delayed or minimal expressive speech
  • Impairment in make-believe or fantasy play
  • Lack of social gestures
  • Conversational skills tend to be one-way (monologues, endless questions etc�...)

Restricted, repetitive behaviours

Patient's may exhibit the following behaviours:

  • The tendency to resist change with a rigid daily routine
  • Preoccupations with specific interests like dates or timetables
  • Inability to adapt to new environments

In addition to ASD, there are many conditions which have increased prevalence in people with ASD. For example, 20-30% of patients will also have epilepsy and around half will have a concomitant diagnosis of attention deficit hyperactivity disorder (ADHD).

Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a condition characterised by deficits in three main domains: social communication, repetitive behaviours, and sensory processing. The prevalence of comorbidities in patients with ASD is seen in Figure 1.

Differential Diagnoses

Differential diagnoses for ASD may include:

  • Global developmental delay: delay occurring in all areas of development, not just social/communication
  • ADHD: difficulties with hyperactivity, attention, and impulse control.


A diagnosis of ASD is based on clinical assessment with deficits occurring across all three aforementioned domains. These features must be observable in all environments that are sufficient to cause impairment in functional capacity. They should have been present from early childhood but may not be fully evident until later when social demands exceed capabilities. There are several formal diagnostic tools for ASD such as Diagnostic Interview for Social and Communication Disorders (DISCO) and Autism Diagnostic Observation Schedule (ADOS).


There is no cure for ASD, but the goal of treatment is to improve day-to-day functional ability and optimise the quality of life. Interventions may need to evolve over time as the needs of the patient evolve with age.

Non-pharmacological therapy

There is a wide range of non-pharmacological support that may be helpful depending on the patient's needs, such as specialist education, occupational therapy, speech therapy, clinical psychology, sleep hygiene, and care agencies.

Pharmacological therapy

There are no specific medications for ASD; however, patients with symptoms of depression and/or anxiety may benefit from behavioural and pharmacological intervention (e.g. SSRIs). In addition, children with sleep difficulties which may benefit from a trial of melatonin if behavioural management/sleep hygiene proved to be unsuccessful.

Practical Tips for Approaching Autistic Patients in Hospital/Appointments

Managing patients with ASD in a clinic or hospital setting can be daunting. The most important thing is to try to put the patient at ease and engage them in their care.

Try not to have too many people in the room, as this may be overwhelming. It may help to have a staff member the patient knows present. Find out in advance how the patient communicates, considering that they may be non-verbal or able to hold a conversation.Pictures or symbols may help, so ask a parent or carer to bring some. Use clear, direct and literal language.

Keep in mind that an autistic child will grow into an autistic adult. The hospital environment can be very stressful for anyone, but particularly for patients with ASD. Having a highly structured and clear routine can help, and it may help to follow a "now and next" pattern, i.e. "Now it's breakfast, next you will see the doctor." It is also important to enable the company of people they trust to reduce stress and calm behaviour.


Patients with ASD may face personal and interpersonal complications, such as social isolation, bullying, problems in education, employment, and inability to live independently.

Key Points

  • ASD is a neurodevelopmental disorder which affects 1 in 100 people, and is more common in boys than girls.
  • ASD consists of deficits in social interaction, communication, and restricted, repetitive behaviours.
  • Management may involve specialist education, occupational therapy, speech therapy, and clinical psychology.
  • Try to communicate with patients with ASD in a way they can engage with.
  • Hospital wards are stressful environments for people with ASD, which may trigger an escalation in behaviour.


  1. ICD-11. Published in 2020. Available from: [LINK]
  2. National Autistic Society. What is Autism? Published in 2020. Available from: [LINK]
  3. BMJ Best Practice. Autism Spectrum Disorder. Published in 2018. Available from: [LINK]
  4. The Lancet Psychiatry. ADHD in children and young people: prevalence, care pathways, and service provision. Published in Available from: [LINK]
  5. Kohane et al. The Co-Morbidity Burden of Children and Young Adults with Autism Spectrum Disorders. Published in 2012. Available from: [LINK]

Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder

Research has found that Attention Deficit Hyperactivity Disorder (ADHD) and Autism Spectrum Disorder (ASD) often go hand-in-hand. Studies have looked into the co-morbidity and explored the factors associated with both conditions.


  • Thapar, A. What have we learnt about the causes of ADHD? Published in 2012. Available from: [LINK]
  • Ganizadeh, A. Co-morbidity and factor analysis on Attention Deficit Hyperactivity Disorder and Autism Spectrum Disorder DSM-IV-derived items. Published in 2012. Available from: [LINK]


Dr Lesley Henderson

Consultant Community Paediatrician


Hannah Thomas

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