1. Autism
  2. Learning about ASD
  3. Assessment & diagnosis

Signs of autism spectrum disorder in older children and teenagers

9-15 years

Children and teenagers with autism spectrum disorder (ASD) typically show difficulties in two main areas. The first is social communication, and the second is restricted and repetitive behaviours and interests.

Signs of autism spectrum disorder

Some of the main social communication and behaviour signs of autism spectrum disorder (ASD) in middle childhood and adolescence are listed below.

These signs often become noticeable when a child reaches school age and has difficulty adjusting to new social situations in a school environment – for example, staying on task, understanding and following instructions, making friends, and having age-appropriate interests.

You might find that some of the signs sound a lot like your child. Others might not sound like your child at all. All children (and adults) have some of the difficulties below. It’s only when enough of these signs are present that your child might get a diagnosis of ASD. A diagnosis of ASD is generally made only when health professionals have ruled out other possible explanations for a child’s behaviour.

If you’re worried about your child, the best place to start is your child’s GP. The GP will be able to refer your child to an appropriate professional.

Social communication signs of autism spectrum disorder

Older children and teenagers with autism spectrum disorder (ASD) typically have trouble with both verbal and non-verbal communication for social purposes.

Verbal communication
An older child or teenager with ASD might:

  • have trouble taking turns in conversations – for example, she might like to do all the talking or find it hard to answer questions about herself
  • talk a lot about a favourite topic, but find it difficult to talk about a range of topics
  • be confused by language and take things literally – for example, she might be confused by the expression ‘Pull your socks up!’ and actually pull up her socks
  • have an unusual tone of voice, or use speech in an unusual way – for example, she might speak in a monotone or with an accent
  • have a very good vocabulary and talk in a formal, old-fashioned way
  • find it hard to follow a set of instructions with more than one or two steps.

Non-verbal communication
An older child or teenager with ASD might:

  • have trouble reading non-verbal cues, like body language or tone of voice, to guess how someone else might be feeling – for example, he might not understand when an adult is angry based on tone of voice, or he might not be able to tell when someone is teasing him using sarcasm
  • use eye contact in an unusual way – for example, he might make less eye contact than others, or not use eye contact when he’s spoken to
  • express few emotions on his face, or not be able to read other people’s facial expressions – for example, he might not be able to tell if someone likes him in a romantic way
  • use very few gestures to express himself.

Developing relationships
An older child or teenager with ASD might:

  • prefer to spend time on her own, rather than with friends
  • need other children to play by her rules
  • have trouble understanding the social rules of friendship
  • have few or no real friends
  • have trouble relating to children her own age, and might prefer to play with younger children or adults
  • have difficulty adjusting her behaviour in different social situations
  • invade personal space and get too close to people.

Behaviour signs of autism spectrum disorder

There are some behaviour signs that a child or teenager might have autism spectrum disorder (ASD).

Repetitive behaviour and interests
An older child or teenager with ASD might:

  • have unusual interests or obsessions – for example, he might collect sticks or memorise football statistics but not really be interested in the game
  • have compulsive behaviour – for example, he might line things up or have to close all the doors in the house
  • have an unusual attachment to objects – for example, he might carry a toy around as a teenager, or collect unusual items like chip packets or shoelaces
  • be easily upset by change and like to follow routines – for example, he might like to sit in the same seat for every meal or have a special order for getting ready in the morning
  • repeat body movements or have unusual body movements, like hand-flapping or rocking
  • make repetitive noises – for example, grunts, throat-clearing or squealing.

Sensory sensitivities
An older child or teenager with ASD might:

  • be unusually sensitive and get upset easily
  • be sensitive to sensory experiences – for example, she might be easily upset by certain sounds, or will eat only foods with a certain texture
  • seek sensory stimulation – for example, she might like deep pressure, seek vibrating objects like the washing machine or flutter fingers to the side of her eyes to watch the light flicker.

Other signs of autism spectrum disorder

Older children and teenagers with autism spectrum disorder (ASD) often have other difficulties as well. These might include:

  • difficulty with sleep – for example, they might have difficulty falling asleep, or might regularly wake up at 4 am
  • anxiety or feeling overwhelmed – for example, they might feel anxious about going to a new place, or being in social situations
  • depression – older children and teenagers who are aware of their differences are also often aware of how others see them and can feel like outsiders. These feelings might be intensified by changing hormone levels during puberty
  • aggressive behaviour – they often have sensory sensitivities that can lead to sudden aggressive behaviour. They might have difficulty understanding what’s going on around them, which can lead to frustration building up
  • eating disorders – for example, they might have difficulty moving to secondary school and might develop an eating disorder to cope with feelings of anxiety
  • difficulty with organisation skills – they might find the increase in complexity at secondary school hard to manage
  • school refusal or not wanting to go to school – they might feel overwhelmed or confused at school.

Autism spectrum disorder: later diagnosis


In this short video, experts in autism spectrum disorder (ASD) talk about older children and young people being diagnosed with ASD. The experts explain why a child might get a late diagnosis. For example, starting high school can trigger anxiety and make teenagers with ASD feel overwhelmed, withdraw socially and feel like they don’t fit in.

The experts use the terms autism and Asperger’s disorder, which have now been replaced with a single diagnosis of ASD.

These signs might be the starting point for a late diagnosis of ASD. Although this can be a huge shock, having a diagnosis can help you get services and funding to support your child’s development.

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Raising Children Network is supported by the Australian Government. Member organisations are the Parenting Research Centre and the Murdoch Childrens Research Institute with The Royal Children’s Hospital Centre for Community Child Health.

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