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Autism diagnostic criteria

Autism diagnostic criteria

Autism spectrum disorder (ASD) comprises a range of neurodevelopmental conditions that impact the child’s behaviour, social skills, and communication skills. While early detection can be difficult, ASD usually starts manifesting in children between the ages of 2 and 4 years. In many cases, the first signs (red flags) can be seen in children as young as 6 to 18 months. There are symptoms related to communication, social skills, and behaviour that become even stronger as the child reaches 2 years of age. 

In this article, we will take you through the standard diagnostic manuals and tools that have detailed autism diagnostic criteria followed by most countries around the world.

Diagnostic manuals

Diagnostic and Statistical Manual, fifth edition (DSM-5)

Released in 2013 by the American Psychiatric Association (APA), DSM-5 is the standard reference widely used by most doctors around the world to diagnose behavioural and mental disorders. 

In 2022, the APA released the DSM-5TR which includes text revisions, citations, some updated criteria, along with the features of a new disorder, prolonged grief disorder.

International Classification of Diseases, tenth and eleventh editions (ICD-10 and  ICD-11)

Approved by the World Health Assembly, ICD-10 addresses the various ASD profiles – childhood autism, atypical autism, and Asperger syndrome. Published in 2022, ICD-11 is an updated and much more detailed version of ICD-10. 

Indian Scale for Assessment of Autism (ISAA)

ISAA is an objective autism assessment tool used by doctors in India to ascertain autism in children. It uses clinical evaluation of behaviour, observation, testing by interaction, as well as inputs shared by family members and caregivers. It consists of 40 items rated on a scale 1 (never) to 5 (always).

DSM-5 diagnostic criteria

Social communication difficulties

This criteria is divided into 3 parts – 

  • Deficits in socio-emotional reciprocity – inability to make two-way conversations, failing to initiate or respond to social cues and interactions, lack of shared interests in a social setting
  • Deficits in non-verbal communication in social interactions – poor eye contact and body language, lack of gestures, no facial expressions
  • Deficits in developing, maintaining, and and understanding relationships – inability to adjust different social situations, cannot make friends, no interest in peers, unable to take part in pretend/imaginative play

Specific behavioural tendencies (stimming, sameness, special interests, sensory sensitivities)

This criteria can manifest in the following ways – 

  • Stimming or repetitive motor movement – lining up toys, echolalia (constantly repeating another’s speech), simple motor stereotyped movements, repeating noises
  • Insistence on sameness – unable to cope with changes in  routine, set patterns of verbal and non-verbal behaviour (for e.g., eat the same food every day, greeting rituals, don’t like transitions, wearing clothes of the same colour every day, etc.)
  • Restricted and fixated interest that may seen abnormal to others – ‘obsessed with unusual objects’ excessively pervasive interests
  • Hyper or hyposensitive to sensory stimuli – indifferent to pain/temperature, fascinated with lights and/or movement, always wanting to smell or touch objects, respond adversely to specific sounds like sirens or loud thumping music

Symptoms presented in early childhood

These may not manifest at a specific time period in all children until social interactions demand certain behaviours. In many undiagnosed cases of ASD these symptoms may get covered up by other skills learned later in life.

Some common red flags in the early years are:

At 6 months: does not reach for objects, does not smile/laugh, does not coo/gurgle, unable to respond to peekaboo and similar games

At 12 months: does not point to pictures/objects, does not respond to their name but can respond to other sounds (cat purring, dog barking, etc.), not said first word yet

At 18 months: no speech, only produces syllables/sounds as heard on television

Impairment in everyday life

Specific symptoms that cause clinical impairment in occupational, social, and other areas of everyday functioning. These may include eating habits, anxiety, etc.

Developmental delays

DSM-5 describes these delays in social communication that are far below the developmental level. These delays should not be mistaken for intellectual disabilities or global developmental delays. 

ISAA diagnostic criteria

Social relationship and reciprocity

  • No social smiles
  • Poor eye contact
  • Remaining aloof in social settings
  • Not initiating interactions with others
  • Inability to relate to peers
  • Not responding to social and/or environmental cues
  • Engaging in solitary and repetitive play
  • Not able to grasp the concept of turn-taking
  • Unable to maintain relationships with peers

Emotional responsiveness

  • Reacting differently in a social setting, instead of showing the expected feeling
  • Displaying emotions in an exaggerated manner
  • Engaging in self talk and self-stimulating emotions in a public/social setting without interacting with others
  • Unaware of hazards and dangers; no show of fear
  • Restless or excited without reason

Speech-language communication

  • Loss of acquired speech (studies show nearly 50% of individuals with autism are mute)
  • Cannot use non-verbal language and gestures
  • Repetitive use of language (include echolalia)
  • Making unusual noises like infantile squeals
  • Unable to initiate and/or sustain conversation with others in a social setting
  • Uttering meaningless speech
  • Using pronoun reversals (saying ‘I’ instead of ‘You’)
  • Difficulty in understanding the real intent or true meaning of others’ speech (for e.g. Can you tell me the time? YES. *but they do not tell the time*)

Behaviour patterns

  • Engaging in repetitive motor movements like body rocking, flapping hands, etc.
  • Overly attached to inanimate objects like stone, pebble, string, bottle, etc.
  • Hyperactivity
  • Aggressive behaviour, especially socially inappropriate behaviour like kicking, hitting, etc.
  • Temper tantrums that manifest in the form of screaming, head banging, screaming, etc. 
  • Harming self by biting, hitting, pinching, etc.
  • Unable to cope with changes to routine, displaying set patterns of verbal and non-verbal behaviour (for e.g., eating the same food every day, wanting things to be kept in specific places and unable to accept any change, following the same set of activities in the exact sequence every day, etc.)

Sensory aspects

  • Hypersensitive or hyposensitive to stimuli
  • Staring into blank space for long periods of time
  • Insensitive to pain
  • Responding to objects by touching, smelling, tasting
  • Has unusual vision – can spot the smallest details, some of which may not even be visible to others
  • Unable to track movement of objects and persons

Cognitive component

  • Poor attention span and inconsistent focus –  even if they do focus on an object, it may be on an irrelevant aspect
  • Lack of quick response to repeated instructions
  • Savant or superior ability – reading early, playing musical instruments at an early age when fine motor skills are still developing
  • Unusual memory – often associated with having an eidetic memory, although some may even be able to recall events that took place in the distant past in their exact sequence

Levels of support

A diagnosis of ASD comes with the required levels of support the child will need. There are three levels that are based on the degree of support the child will need. They are:

Level 1 – Requiring support

At this level, support is essential to overcome challenges in social communication. The child may also appear less interested in initiating social interactions. Support at this level is simply given to help the child along only at the social level. 

Level 2 – Requiring substantial support

At this level, the support offered to the child is to help understand social cues, participate in verbal and non-verbal communication, initiate conversation, and reduce abnormal response to social overtures made by others

Level 3 – Requiring very substantial support

Children may find it extremely difficult to partake in verbal and non-verbal communication, to the extent that it interferes with their daily functioning. They are unable to adjust to the littlest of changes to their routine and hardly respond to social cues and dialog. Support at this level addresses these behaviours. 

Treatment and care with Plexus

An ASD diagnosis can change your world upside down. But your child’s world remains the same. We need to alter our outlook and realise theirs is a life that is equally bright and full of potential. At Plexus, we offer the best autism treatment plans for your child. Holistic, timely, and tailored to suit your child’s needs and lifestyle, we offer a wide range of therapies and treatments that have led to significant improvements in the lives of children with autism.

Our treatment plans include:

  • Sensory integration therapy
  • Behaviour retraining therapy
  • Cognitive behaviour therapy
  • Social skills training
  • Improved awareness
  • Speech therapy
  • Reduction in hyperactivity

Don’t let an ASD diagnosis pull you or your child down!

To book an appointment with us, please call on

+91 89048 42087 | 080-2546 0886

080-2547 0886 | 080-2549 0886


What is the DSM-5 criteria for autism?

DSM-5 is a diagnostic manual released by the American Psychiatric Association to diagnose behavioural and mental disorders.

Its criteria for autism includes:

  • Difficulties in social communication
  • Repetitive, restrictive, sensory interests or behaviour
  • Symptoms presented in early childhood
  • Impairment in everyday life
  • Developmental delays

What test can confirm an autism diagnosis?

The Autism Diagnostic Observation Schedule (ADOS) is the most widely recognised ‘gold standard’ for diagnosing and assessing autism and pervasive developmental disorder across all ages, developmental levels, and communication skills.

What is the most common autism test?

The Ages and Stages Questionnaire (ASQ) and Screening Tool for Autism in Toddlers and Young Children (STAT) are the most widely used screening and assessment tools.

What does mild autism look like?

Repetitive behaviours, not understanding social cues, inflexible adherence to routines are some signs of mild autism. However, this can differ from case to case.

Can a mildly autistic child go to normal school?

Yes, as long as the teachers and school authorities are aware of the child’s condition. Remember, the right school is the one that offers support and is empathetic.

Is speech delay a symptom of autism?

Yes, speech delay is a common symptom of autism. However, studies have shown that early exposure to screens (television) can also cause speech delay in young toddlers.

Can you be just slightly autistic?

Simply put, no. There’s no such diagnosis as ‘slightly autistic’. Depending on where the child is on the ASD spectrum, their diagnosis can be mild to moderate to severe.

What are autism triggers?

Every individual will have their own threshold, but the most common autism triggers are sensory differences, anxiety, changes in routine, and communication challenges.

Does autism come from the mother or father?

Research indicates rarer variants of ASD are mostly inherited from the father. However, even if there is no family history of autism, studies have shown that there are several autism-inducing genetic mutations. These are spontaneous – meaning it has not been inherited from either parent.

Does stress cause autism?

Maternal stress (when pregnant) has been associated with the increased risk of developing ASD. Children who have experienced multiple stressors like separation anxiety, physical/emotional trauma, fear of the unknown, bullying, etc. may also be at risk of developing ASD.

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