Autism Symptoms in Children and Adults

Signs and Symptoms of Autism Spectrum Disorder

Autism spectrum disorder (ASD), or autism is a broad classification used to represent diverse neurodevelopmental conditions. According to the World Health Organization, 1 in 100 people get diagnosed with autism.

The number of signs of autism as well as when and how they will appear varies from person to person. Some symptoms of autism are present in neurotypical children as well. However, with proper awareness and knowledge, it's easier to understand how autistic people have different ways of learning, communicating, as well as exhibiting certain patterns of behaviour.

Characteristics of Autism

The DSM outlines autism as a condition spanning a spectrum due to its varied symptoms and impacts on individuals. Each person's experience with autism differs greatly, presenting a range of challenges and behaviours. This spectrum perspective acknowledges the diversity within the disorder, where some may struggle with verbal communication while others excel.

It is also crucial to note that the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) lists three levels of autism spectrum disorders. Therefore, symptoms of level 1, that is, high-functioning autism would be less pronounced and easier to overlook or don't warrant immediate diagnosis. Whereas, level 3, that is, low-functioning autism represents more pronounced symptoms.

Symptoms of Autism

The signs and symptoms of autism spectrum disorder vary and can occur at different times, for example, some people show the symptoms within a few months of birth while others do not show any symptoms until age 2 or much later.

Regardless, the symptoms of autism do become evident during the early stages of childhood, typically between 12 months to 24 months. Every autistic person’s needs are unique. Therefore, understanding the symptoms as well as how they manifest in different ways at different stages of life becomes important.

There are two core symptoms of autism which are also described in the DSM-5-TR. These two core symptoms are looked for by doctors for the diagnosis of autism spectrum disorder.

The two categories of symptoms are:

  • deficit in social communication and interaction
  • repetitive or restricted patterns of behaviour

Both of these categories of symptoms are manifested in different ways in every autistic person. Moreover, both of these categories of symptoms must be present in a person to be diagnosed with autism.

Deficits in Communication and Interaction Skills in Autism

Deficits in social communication skills refer to both verbal and non-verbal communication. Children and adults with autism struggle to communicate or engage in back-and-forth communication.

They might also be unable to share what they are interested in as well as find it difficult to express their emotion. Autistic children and adults also find it difficult to understand others' nonverbal cues and body language as well as thoughts and feelings. They would also find it difficult to understand jokes and sarcasm.

Initiating and maintaining eye contact is found to be uncomfortable for autistic people. However, this does not mean that they are not paying attention to a conversation or situation. As infants, instead of looking at faces and expressions of others, they would rather prefer looking at inanimate objects.

Autistic people might have a very monotone, robotic or singsong voice. Sometimes, they are also unable to modulate the tone of their voice, so some might speak very loudly or very quietly.

Autistic people also exhibit deficits in learning skills and delayed speech. They might get fixated with some particular topic of interest and develop an extensive vocabulary for the topic alone.

However, the difficulty with communicating about other things and social conversations might still persist. They might also have problems with pronouns (using third-person or second-person pronouns instead of first).

Hyperlexia refers to reading beyond what's expected of one's age. Research (Ostrolenk et al., 2017) suggests that 84 per cent of children who have hyperlexia are found to also be on the autism spectrum. It has also been found that while children with autism can read earlier than their peers, they are unable to comprehend what they read.

Autistic adults and children also get anxious in social situations. They might find these situations overwhelming and are also unable to make friends or maintain a relationship with their peers. They also lack comprehension about boundaries and personal space.

These deficits, as they begin to appear in early childhood, are persistent throughout adulthood.

Restricted or Repetitive Patterns of Behaviour in Autism

Children and adults with autism might show repetitive movements like rocking back and forth, flapping their hands continuously, spinning in one spot or running. They show “hyper” behaviour. This means that they are always constantly moving.

They might also repeat words or phrases, a phenomenon known as Echolalia. This also refers to imitating someone else's speech. Some autistic children also exhibit Echopraxia, which is, the repetition of words and phrases with actions. However, this is mostly rare and echolalia is a more common symptom.

Children and adults with autism are obsessed with the maintenance of a routine. Autistic children might line up their toys in a fixed order and get upset when that order is disrupted.

Moreover, they also prefer having a fixed routine such as a fixed bedtime ritual, getting reading for school routine, etc. This attachment to routine is such that if it is replaced or if there are minor changes, it would lead to intense crying and heavy tantrums until the routine is restored.

Autistic children and adults also show strong attachment to certain objects such as light switches, rocks, textured materials, etc. They might also get fixated on narrow topics and seek information and knowledge about them. These interests can be classified as obsessive.

Autistic people also react differently to sensory stimuli compared to their neurotypical peers. They respond differently to certain senses like taste, sound, light, and texture.

For some, even seemingly mild sensations can be overwhelming. Conversely, there may be a lack of sensitivity to pain or temperature, leading to potential safety concerns.

Additionally, sensory-seeking behaviours are common among those with autism, such as engaging in repetitive actions like smelling or touching objects, or showing a fascination with lights or movement.

Other Common Symptoms of Autism

  • Impulsivity
  • Specific eating habits like being a picky or fussy eater.
  • Lacing fear or being extremely fearful
  • Deficits in motor and cognitive functioning (such as difficulty in making decisions, carrying out tasks, etc.)
  • Difficulty in managing and expressing emotions leading to harmful behaviours, sensory overload, meltdowns, or shutdowns.
  • Gastrointestinal issues
  • Inability to understand social cues, norms and rules

Early Signs of Autism

It is possible to miss signs of autism in childhood and only receive a diagnosis in adulthood. Mildly autistic children may display subtle neurodivergent traits amidst typical behaviour, often mistaken as personality quirks.

Although some caregivers may notice unusual behaviours, they may not prompt immediate diagnosis.

Early signs of autism can appear right from infancy and some might get even more pronounced as the child gets older. An earlier intervention for autism is often seen as more effective.

Therefore, it is the responsibility of the parents, guardians and caregivers to pay attention to the developmental milestones of their children.

For better understanding, this article mentions a timeline that helps one understand the early signs of autism.

From Birth: The child has trouble maintaining eye contact. There is limited to no eye contact.

By 6 months: The child does not show engaging expressions, smiles or emotions.

By 9 months: There is limited or absent reciprocal exchanges of sounds, smiles, or facial expressions. The facial expressions of the child does not reflect their emotions such as anger, joy or surprise. The child is also unresponsive and does not react to their name.

By 12 months: The child pays more attention to inanimate objects than people. Unlike their neurotypical peers, the child does not engage in games like peek-a-boo or pat-a-cake, both of which are highly interactive.

Gestures such as pointing, waving, reaching out for objects, which are common ways for communication by this age are not seen or rarely seen in an autistic child. At this age, the child does develop language skills but then shows a decline in those skills.

At this age, the child might not babble at all, or their babbling does not sound like they are trying to hold a conversation. They do not smile back when others smile at them.

By 15 months: They stop sharing about things that they are interested in with others. Such as showing a toy they like to their caregivers or peers or sharing thier toys with others. They might show difficulty in understanding simple, one-step instructions, even from their same-aged peers.

By 18 months: It might appear that the child is not hearing when directly spoken to. The child might speak little to no words. The child also does not engage in pretend play, such as playing house with dolls or pretending to cook food or having a tea-party.

The child might also have an unexpected way or ritual with playing with the toys. The child also does not point at things or looks where others point at things.

By 24 months: The child has fixation on certain topics and shows interest to certain objects. They repeat words and phrases without seeming to understand them. At the same time, they seem to utter very few or no meaning words or phrases.

They usually self-isolate and might exhibit self-injurious behaviours like banging their head. They don’t show interest in playing or engaging in activities with other children of the same age.

They like having a routine and having things be a certain way, such as eating food cut up in the same shape, having a specific bedtime ritual, etc.

What is Stimming in Autism and Does It Matter?<

Stimming or self-stimulation are relative body movements or movement of any inanimate objects such as marbles, rubix cube or rocking or spinning, that many individuals in the autism spectrum display. Research states that the reason why a person engages in stimming varies with different people.

Self-stimulating behaviour is not unique to neurodivergent people and it is seen in neurotypical people as well. For example, it is a common motion to tap one’s foot or twirl one's hair when someone is impatient or stressed.

Many individuals on the autism spectrum report that stimming is a way for them to adapt to their environment which usually only caters to neurotypical people. There are various purposes for stimming such as:

  • To counteract sensory overload
  • To reduce feelings of overwhelm in social situations and counteract anxiety
  • To main attention
  • To seek pleasure

While these might not seem harmful, stimming can pose a risk if it interferes with meaningful activities.

Stimming behaviors can also serve as signals for caregivers, teachers, or employers to recognize when individuals need a break from their environment. While not all stimming needs to be eliminated, it's important to assess the behavior and determine when and where it is acceptable.

What is Masking of Symptoms in Autism?

Masking refers to the subconscious or not consciously made attempt by neurodivergent people to act in ways that seem natural to neurotypical people. This is usually done by people to meet the societal framework and to blend into their peers and colleagues.

This can include an autistic person trying to suppress their desire to stim or reaction to overwhelming situations such as sensory overload.

Masking also includes behaviours like :

  • Forcing oneself to make eye contact
  • Having a set of rehearsed responses that can be used in a conversation
  • Learning to imitate facial expressions
  • Trying to hide one’s stimming
  • Trying to overcome or push through the sensory overload

Autism masking can take a huge amount of mental effort and therefore lead to burnout and depression. Masking can also lead to delayed diagnosis for those with mild autism.

Autism in Adults

Signs and symptoms of autism develop from children and persist throughout adulthood. It is common for people with high-functioning autism to be misdiagnosed with other disorders like ADHD in their childhood and not receive the diagnosis of autism until adulthood.

If you suspect that you or someone you know might be autistic, familiarizing yourself with the common signs of autism is the initial step toward recognizing potential undiagnosed autism specturm disorder.

Common symptoms of autism in adults include

  • Difficulty in making eye contact
  • Pefers solitude over social interaction
  • Difficulty in making friends
  • Gets upset when someones touches or gets close
  • Lack of understanding of social cues and boundaries
  • Very keen interest on specific and narrow topics
  • Conversing in a really blunt way
  • Not understanding jokes and things very literally
  • Following the same routine everyday
  • Noticing minute details that others wouldn’t

Autism in Women

Autism in women has often been overlooked due to differences in presentation and diagnostic biases. Females may display less overt symptoms and engage in camouflaging behaviors, making diagnosis challenging.

Their social difficulties may be masked by societal expectations, leading to misdiagnosis or delayed diagnosis. Additionally, autistic traits in women may manifest differently, further complicating recognition.

Accessing appropriate support and services can be difficult due to lack of awareness and stigma. However, increased awareness, research, and advocacy efforts are beginning to shed light on the unique experiences of women with autism, highlighting the need for better recognition and support.


In conclusion, autism spectrum disorder presents diverse challenges and behaviors, spanning from childhood into adulthood. Understanding and recognizing the signs of autism, as well as the unique experiences of individuals across the spectrum, are crucial steps towards providing support and fostering acceptance in society.

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