I have been in this field for 22 years or so, and a BCBA for almost 15 years. Throughout that time, my clinical values have evolved from treating hyperfocus/intense interests as a problem to treating them like a core value that should be encouraged and utilized to bring joy. Some ways this can be done is to expand activities using that interest, i.e., Thomas the Train coloring books, Thomas the Train video games, or Thomas the train toothbrush. It can also be used to build peer engagement by finding peers that share the interest.
This is important because we, as BCBAs, often treat what we define as a “restricted interest” as something that must be immediately controlled. However, I have been thinking a lot about this in relation to fandoms. If you have ever visited a ComicCon you will see that any member of a Fandom is intensely dedicated to their interest. I am not Autistic, and I love Doctor Who. My house is covered with memorabilia, pictures from AwesomeCon where I stood in line for hours to get photos with my kids and the actors, and every night my whole family watches an episode. Yet, this is socially acceptable.
I have also been thinking about how this applies to obsessions with celebrities which is its own type of fandom. Swifties- often neurotypical girls- want to know every fact about Taylor Swift and her songs. They know all the lyrics, every fact about her boyfriend, and spend hours watching videos to see if there are Easter eggs about new album releases. Studies suggest that Autistic girls are more likely to gravitate towards more "socially appropriate restricted interests" like horses or bands. While I haven't seen research, it seems likely Taylor Swift is a prime candidate for hyper-focus. As a result this gives social currency for Autistic girls who know this information. So, hyper-focus and the ability to collect, retain, and share information can be a valuable social asset.
Similarly, when Pokémon Go came out, I observed that our clients that were "hyper focused" on Pokémon suddenly had many neurotypical peers to download their knowledge into. It was no longer an unusual interest, but a popular topic. They could go to a spot on the playground with their phone and someone would walk up to them; they could just talk about Pokemon and everyone was riveted. Their interest in Pokémon in the past wasn’t a problem with them, it was about who they were talking to.
At what point is it fandom, and at one point is it hyper focus? Is that point when you have people who are as interested in it as you are? We need to stop thinking about special interests as a problem. We need to think about it as needing to find the right conversation partner.