Autism Spectrum Disorder

ABC of ASD (Autism Spectrum Disorder)

This is a fact-first primer on Autism Spectrum Disorder. It aims to inform, and sensitise caregivers, peers and all readers about what this condition looks like, means medically, and the developmental differences it comes with. TSC will keep adding sections to this post to aid a complete and compassionate understanding of people on the spectrum.

If looks could talk, they’d say nothing about Autism Spectrum Disorder

Persons with this developmental disorder hide in plain sight. They look like other people of their age, can have an average to above-average intelligence and their behavioural giveaways — unless severe — can often be dismissed as peculiarities. Prevalence of prejudice and stereotypes, and absence of any diagnostic tests make it particularly difficult to catch it

Hide as ASD may, there is a long but comprehensive checklist of symptoms that help through screening tests that are used for diagnosis.

Before we deep dive into ASD, let’s look at some data that shows exactly how common it is, and that a condition affecting the lives of millions of people is worth understanding whether we personally experience it or not.

  • Autism is the third most common [5] developmental disorder, more common than Down Syndrome.
  • Globally, 1 in 68 children are on the Autism spectrum (CDC, 2014). In India, this number is at ~1 in 100 children under the age of 10 [2].

Boys are 3-4X more likely to have Autism than girls. This prevalence, and the difference in its presentation among girls, is also the reason why ASD goes undetected or is detected as late as early adulthood.

What is Autism Spectrum Disorder (ASD)?

Autism is a lifelong neurodevelopmental disorder — arising in the developing years starting from birth but becoming most noticeable from 2 months to 5 years of age — that presents itself in a wide range of forms and levels of severity. 

It can co-occur with intellectual disability, besides other conditions, but not necessarily. The cognitive capacity of a person with ASD can range from gifted to severely challenged (IQ range: <70 to >120).

It is a group of conditions — Autistic disorder, Pervasive developmental disorder not otherwise specified (PDD-NOS), Asperger syndrome, Rett syndrome, Childhood disintegrative disorder, and Kanner’s syndromethat were earlier diagnosed separately.

Having ASD means the child or adult will have persistent challenges in three main areas:

  • communication (verbal and non-verbal),
  • social adaptation,
  • restricted interests and repetitive behaviour.

These are called the triad of impairments that affect the behaviour in predictable ways.

These impairments mean that persons with ASD will experience the world — communicate, interact, behave, and learnin ways that are different from their typically developing peers. Their atypicality can be misunderstood for ‘disobedience’ or ‘bad behaviour’, when what’s at play is a difference in brain function.

Sometimes, the condition may affect gross motor abilities, result in facial twitches, jerky movements depending on the co-occurrence of other conditions. These co-occurring conditions have a great impact on how much assistance a child will require. While some with ASD may need a lot of help with their daily lives, others may need less.

Causal Factors

Just like there is no one type of autism, there is no one known cause of it either. While scientists are studying genetic and environmental contributors, existing research shows there are several factors that can increase the risk of a child being born with ASD. But, a risk factor is not the same as an identified cause.

Some of the known risk factors are:

Genes. ASD tends to run in families. If a child has ASD then it increases the chances of their sibling having it as well; the manifestation can differ. However, the parent may or may not have the same condition.

Fragile X syndrome is a leading genetic cause of autism. About one in three people with the syndrome also has autism. 

Pregnancy complications like maternal diabetes, high blood pressure or autoimmune disease, use of antipsychotic drugs or antiepileptic drugs [1], severe viral infections like Rubella are linked to autism. Measles and mumps viruses can cause encephalitis that can result in autism later [4].

Environmental risk factors that increase the child’s predisposition to ASD include premature birth, low birth weight, and being born in under one year of sibling’s birth.

Scientists are also discovering a possible link between ASD and exposure to chemicals or pollutants in the third trimester [1].

Checklist of Symptoms

The triad of impairments — communicative, behavioural and social —is the biggest ASD indicator. But one of the main characteristics of autism is uneven skill development making the condition very difficult to diagnose, especially in the absence of genetic and medical tests. Only assessment tools are used by experienced paediatricians to make a diagnosis.

For example, all the skills of a typically developing child at 5 years of age will be consistent with those of other children their age. In the case of a child with ASD, it is not so. They may be 4 years old but have the speech skills of a 2-year-old, gross motor skills of a 7-year-old, fine motor skills of a 5-year-old, and self-care skills of a 3-year-old. Older children may show skills for math and languages beyond their years, but may not be able to communicate their needs or wants.

So, it becomes extremely important to thoroughly examine the child before making a diagnosis which is based on developmental history (assessing delays) and behaviour.

While ASD can be diagnosed as early as 18 months, a reliable professional assessment can be made by 2 years of age. At the same time, for some kids, a complete diagnosis may take longer based on the symptoms as they appear, which usually happens when social demands exceed capacity. 

It is also important to remember that for ASD these social and behavioural symptoms are not better explained by an intellectual disability, which commonly co-occurs with autism.

Here’s a complete list as per DSM-5 [3]:

  1. A) Social communication and social interaction
  2. Deficits in social-emotional reciprocity.
  3. Failure of normal back-and-forth conversation.
  4. Reduced sharing of interests, emotions, or affect.
  5. Failure to initiate or respond to social interactions.
  6. Poorly integrated verbal and nonverbal communication.
  7. Abnormalities in eye contact and body language.
  8. Deficits in understanding and use of gestures.
  9. Total lack of facial expressions and nonverbal communication.
  10. Deficits in developing, maintaining, and understanding relationships.
  11. Difficulties adjusting behaviour to suit various social contexts, such as lack of interest in imaginative play or making friends or absence of interest in peers.
  12. B) Restricted, repetitive patterns of behaviour, interests, or activities
  13. Repetitive motor movements, use of objects, or speech, for example lining up toys or flipping objects, echolalia, idiosyncratic phrases.
  14. Insistence on sameness, inflexible adherence to routines, or ritualized patterns or verbal nonverbal behaviour; smallest changes result in extreme distress including those with food, difficulty transitioning, rigid thinking patterns.
  15. Highly restricted, fixated interests with heightened intensity or focus, aka attachment or preoccupation.
  16. Under- or over-sensitivity to sensory input, such as indifference to pain/temperature, adverse response to specific sounds or textures, excessive smelling or touching of objects, visual fascination with lights or movement.

Conditions That May Co-occur With Autism

  1.   Attention Deficit Hyperactivity Disorder (ADHD)
  2.   Intellectual Disability (previously known as mental retardation)
  3.   General Anxiety Disorder (GAD)
  4.   Depression
  5.   Seizures and epilepsy
  6.   Specific Learning Disorder (LD)
  7.   Cerebral Palsy (CP)
  8.   Hearing impairment
  9.   Visual impairment


There is no medical test to diagnose ASD. Doctors have to observe the child’s behaviour and milestone delays, coupled with parent interviews to arrive at a conclusion.

Screening tools commonly used in India include:

ARI’s Diagnostic Checklist, Form E-2, by Dr Bernard Rimland. It is used to diagnose children with ‘classical autism’, but it is now being used by parents and professionals to assist in the diagnosis of ASD. The responses on this checklist are entered into a computer which calculates a diagnostic score. There is no charge for this service.

Ages & Stages Questionnaires (ASQ) is a developmental screening tool for children from birth till the age of 6 years. It is an easy-to-use parent-centric developmental screening test and the most widely used across the globe. The responses are discussed to come up with next steps for a child’s care.

Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R), is a 2-stage parent-report to assess risk for Autism Spectrum Disorder. It asks a series of 20 questions about the behaviour of a child between 1.5 years and 3 years. The questionnaire is available for free download for clinical, research, and educational purposes.


Early detection ensures the journey to help a child reach their full potential starts as early as possible, many times the signs of ASD can be missed. An increasing number of adults, especially women — in whom ASD presents differently than men — are opting for diagnosis in adulthood after observing their own symptoms and seeking help.
There are no standard diagnostic criteria for adults with suspected ASD, but they are in development. If you feel you or someone you know may be on the spectrum, approach a clinician or reach out to The Sarvodya Collective to understand yourself better and how you relate to the world.