If you or your family are neurodivergent in some way, you may have come across the terms hyperfocus or hyperfixation, special interest, and stimming.

These behaviours are common in people with ADHD, autism, or both. They're often assumed to be the same thing but are actually three distinct behaviours – though they can occur in the same person, and at the same time.

So, what is stimming?

‘Stimming’ comes from the ‘self-stimulatory behaviour’ and is often seen in people with autism. It refers to repetitive actions that help someone self-regulate their behaviour, feelings, or moods.

Common stims are hand-flapping and rocking, but can also include other repeated actions such as flicking or tapping fingers, pulling or twirling hair, flexing feet, or fidgeting with jewellery or clothes.

Stimming does not have to be a movement; it can also include repeatedly singing or saying a phrase, listening to something over and over again, or watching something happening repeatedly. Someone may start doing a stim without noticing, but once identified, it can be done purposefully as a coping mechanism.

Why do people stim?

Stimming provides consistent sensory input in an environment where the person is receiving inconsistent or overwhelming sensory input – the input could be external such as loud noise in a supermarket or other public place, or internal, such as ‘noisy thoughts’ or a strong emotion.

The strong emotion doesn’t have to be negative. Autistic people frequently stim in response to strong feelings of happiness or excitement. It has been reported that stimming when happy can actually accentuate the positive emotions, making the autistic person even happier.

Are there any downsides?

Research suggests that stimming is by and large a positive activity, and that the biggest negative is other peoples' reactions to it. At various times, "treatments" to control or reduce someone’s stimming have been popular but thankfully that's changing as autistic people explain and advocate their need for stimming.

Some parents may try to reduce stimming in their child for fear of stigma, but this can result in them feeling stifled or even more overwhelmed and may cause them to find stims that are less obvious but maybe more harmful.

Harmful stims can include excessive hair-pulling, skin picking, and banging or hitting limbs or the head. Providing different and less damaging sensory input at times of distress may be a useful way to redirect the child away from harming themselves. Examples include strong hugs that provide full body pressure, or a hand firmly pounding their back to provide a rhythm. Rocking chairs and sensory swings can also assist in providing rhythmic input.

Can stimming occur alongside hyperfixation and special interests?

Yes, it's possible that someone with ADHD and autism might exhibit hyperfocus on a special interest while stimming. For example, if someone loves stimming by chewing on silicone jewellery, they might get curious as to how it’s made and start looking online, triggering the creation of a special interest. There are a lot of videos on YouTube of how silicone is coloured, or how different silicone products are made in factories, and so this person might watch them obsessively, enjoying the repetitive nature of the video (a visual stim), while learning about the process and then telling all their friends and family members about it (also known as ‘info dumping’). They may do this research for hours at a time and be difficult to distract from the topic or unable to notice what’s happening around them while engrossed in that activity (hyperfocus).

Stimming is a normal activity for a neurodivergent person and is not usually a cause for concern. If you're worried about a particular behaviour, talk to your child or observe them quietly when they are doing it, and see if you can figure out why this particular behaviour is useful or rewarding for them. That ought to give you some guidance on what other less-worrisome activities may be attractive to your child so you can start slowly introducing new stimuli and redirecting their behaviour.

Learn more about stimming

‍Repeated movements and behaviour (stimming) from the National Austistic Society (UK) which shares autistics’ views on stimming.

Altogether Autism (an NZ organisation) has a YouTube channel with a couple of shorts that mention stimming or special interests:

• ‍Should you encourage stimming in the workplace?
• ‍Autistic people answer: What are your hobbies and interests

What to know about repetitive behaviors in autism (from The Transmitter, aimed at neurotypical parents to help them understand stimming)

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We have also linked to some free resources from the IHC Library below.

But if there’s something else you’re looking for, please reach out to the IHC library for a chat on 0800 442 442 or email librarian@ihc.org.nz