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Self-injurious behaviour

Self-injurious behaviour is where a person physically harms themselves.

It's sometimes called self-harm. This might be head banging on floors, walls or other surfaces, hand or arm biting, hair pulling, eye gouging, face or head slapping, skin picking, scratching or pinching, forceful head shaking.

About half of autistic people engage in self-injurious behaviour at some point in their life, and it can affect people of all ages.

Possible Causes

There might be a number of factors causing someone to self-injure, for example

  • feeling they are not listened to
  • they have been told off
  • they have little or no choice about things
  • they have been bullied
  • they are involved in arguments, or hear other people arguing
  • they are feeling unwell
  • they have memories of a bereavement
  • they have memories of abuse


The person might have no other way of telling you their needs, wants and feelings. Head slapping, or banging the head on a hard surface, may be a way of telling you they are frustrated, a way of getting an object or activity they like, or a way of getting you to stop asking them to do something.

Hand biting might help them cope with anxiety or excitement. They might pick their skin or gouge their eyes because they are bored. Ear slapping or head banging might be their way of coping with discomfort or saying that something hurts.

Mental health issues

Some self-injurious behaviour might indicate mental health issues such as depression or anxiety.

Repetitive behaviour

Some forms of self-injury might be part of a repetitive behaviour, an obsession or a routine.

Developmental stages

The person might still do some things that most people stop doing as young children, such as hand mouthing - putting their fingers or hand into their mouth - causing injury.

Learned behaviour

The person might learn that self-injurious behaviour can be a very powerful way of controlling the environment. A behaviour, eg head slapping, which they did at first because of physical pain, could eventually become a way of avoiding or ending a situation they don't like, eg turning the television off, or interrupting an argument taking place nearby.

What to do when it happens

Here are some pointers on things you could do when the behaviour is happening. In extreme circumstances or emergencies, call 999. You should also try to find ways to prevent the behaviour happening.

Respond quickly

Respond quickly and consistently when the person self-injures. Even if you think what the person is doing is to get attention, it's never appropriate to ignore severe self-injurious behaviour.

Keep responses low key

Limit verbal comments, facial expressions and other displays of emotion. Try to speak calmly and clearly, in a neutral and steady tone of voice.

Reduce demands

The person might be finding a task too difficult or overwhelming. If it's a task that needs doing, come back to it later when the person is feeling calmer.

Remove physical and sensory discomforts

Smells, sounds or tastes might be causing the person distress. If there's a smell that's bothering them, take the smelly thing away, or take the person to another room. If their clothes are uncomfortable, prompt them to change. If it's noisy outside, close the window or offer ear defenders.


Tell them what they need to do instead of the self-injurious behaviour, eg ''David, hands down''. Use visual cues such as picture symbols to back up instructions. Redirect to another activity that can't be done at the same time as the self-injurious behaviour, eg an activity that needs both hands. Give praise when they switch to the activity, eg ''David, that's excellent playing with your train''.

Provide light physical guidance

If the person is having difficulty stopping the behaviour, provide light physical guidance, eg gently guide their hand away from their head, using as little force as possible. Immediately try to redirect their attention to another activity and be prepared to provide physical guidance again. This approach must be used with extreme caution as it may escalate the behaviour or cause the person to target others.

Use barriers

Place a barrier between the person and the object that is causing harm. For head slapping, place a pillow or cushion between the head and hand. For hand or arm biting, provide another object to bite down on. For head banging on a hard surface, place a cushion or pillow between the surface and the head.

Preventing self-injurious behaviour

Ask a health professional for help with any self-injurious behaviour which is difficult to manage or which places the person at risk of harm.

Rule out medical and dental causes

Visit the GP or dentist. Bring along notes about the behaviour - what time of day it happens, in which situations, how often it happens, when it first started, and how long it lasts.

Think about the function of the behaviour

Complete a behaviour diary (see additional link on how to create a behaviour diary), which records what is occurring before, during and after the behaviour. This could help you to understand the purpose of the behaviour. Make notes on the environment, including who was there, any change in the environment and how you think the person was feeling.

Increase structure and routine

Create a clear daily routine. This will make things more predictable and could reduce anxiety. Put a range of activities into the routine. This will reduce boredom and leave fewer opportunities for the person to engage in self-injurious behaviour. Make plans for difficult times of the day, providing more supervision and support at these times.

Provide sensory alternatives

Build alternative sensory experiences into the daily routine. Jumping on a trampoline or swinging on a swing might provide a similar sensory experience to head shaking or slapping. Providing the person with a bag of safe objects to chew on - gum, carrots, raw pasta or sultanas - might reduce the need for hand or arm biting.

Remove or reduce access to danger if possible

If there are particular risks, for example from knives, keep these out of the young person’s reach or locked away. Cupboard locks can be useful for younger children, for example:

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Use communication tools

Support the person to use other ways of communicating their wants, needs and physical pain or discomfort. You could try pictures of body parts, symbols for symptoms, or pain scales, pain charts or apps. More information about visual supports is available on The NAS website:

Reward appropriate behaviours

Give encouragement to the person for appropriate behaviour and for periods when they did not engage in self-injurious behaviour. This will help them learn that other behaviours bring positive outcomes.

Rewards can be verbal praise and attention, a favourite activity, toys, tokens or sometimes small amounts of favourite foods or drinks. Say clearly what it is that you are rewarding, and give the reward straight away.

Some autistic people don't enjoy social attention. Verbal praise could cause distress and have the opposite effect to the one you wanted.

In extreme circumstances or emergencies, seek support from your GP or outside of surgery hours, via Accident and Emergency Services.


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