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

These are three types of behaviour that are very common in people with ADHD, autism, or both. They can often be assumed to be the same thing but are actually three distinct behaviours that can nevertheless occur in the same person and at the same time.

We're going to do a series on all three.

Our first resource was on hyperfocus or hyperfixation. Our third was on stimming.

This post will be about special interests.

In autism, special interests are very common. This is when someone has an intense focus on a specific activity or topic of interest and wants to know everything about it. Their knowledge level on this topic is often described as “narrow but deep”. It may be difficult to shift their attention, and they may have difficulty disengaging from focusing on the details of this topic.

Resistance to being redirected is often because this topic or task is familiar. In previous articles about neurodivergence, we’ve said “In the absence of routine, focus on certainty”.

Uncertainty can be anxiety-inducing for autistic people, and so repetitive activities with predictable outcomes or more information on the topic of choice are likely to be calming or soothing.

Special interests are often about systems – analysing, exploring, and constructing them. This is why special interests are often topics where there are taxonomies (e.g. animals, dinosaurs, insect types) or clear connections or patterns (such as railways, the environment, the solar system). The most well-known special interests are often stereotypically male-gendered topics, but special interests do occur in girls as well. For example, an autistic girl might be obsessed with horses or has read every single Babysitters Club book. Autistic teenagers often know everything there is to know about a particular popular band.

Similar to hyperfocus in ADHD, it’s possible for people with autism to use their special interest as a ‘superpower’, by studying the interest at a high level or working in a particular field of interest.

Sometimes it can be important to redirect your child away from a special interest that looks like it could cause harm. If you’re worried about a special interest your child is developing, try to figure out what it is about that topic that has triggered their interest and slowly introduce related but less harmful information to steer them away from the harmful input.

For example, the pandemic means they may start researching the different strains of Covid-19, which can end up triggering anxiety. Parents could provide information about other viruses and the vaccinations and treatments that have been developed to assist. The similarity in systems may be soothing and interesting to the autistic child and provide some reassurance about our current situation.

It is also possible for a particular behaviour that’s part of a special interest to be mistaken for stimming as the difference can be difficult to distinguish, depending on how the focus is being expressed.

It is possible that someone with ADHD and autism might exhibit all three of the behaviours in this series, by hyperfocusing 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).

Special interests are normal for a neurodivergent person and is not usually a cause for concern. If you are 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.