I don’t really want to write about this, since I have a lot of difficult personal feelings about this topic, but if you look into any further information about autism it’s likely to come up, so here I go.
In addition to stims that look a lot like typical fidgets, and unusual but harmless stims like hand flapping or spinning in circles, some autistic people do things that are similar to stims, but are self-harming.
The classic examples are hitting oneself and head-banging.
In keeping with the overall assumption that autistic people’s stims are involuntary and meaningless, doctors tend to call these things “self-injurious behaviors” or “SIBs” rather than “self-harm”, and treat them as a behavior that autistic people need to be trained out of, rather than an indication that autistic people who do them are depressed or emotionally overwhelmed.
Autistic “SIBs” do often come from emotions– anxiety, stress, etc. But the popular conception of self-harm doesn’t really fit SIBs, either. This is something that I’ve struggled to understand about myself. I did things that certainly looked like self-harm, but I felt very strongly that they didn’t fit into what I was told self-harm was. I wasn’t depressed. I wasn’t suicidal. I wasn’t self-hating. I wasn’t particularly filled with any negative emotion. But I was pretty sure that if I said any of those things, people would tell me I was deep in denial at best. I felt that I had to stop doing anything remotely self-harming, not because it was actually bad for me, but because it upset other people and there was no way I could change their minds.
What does that actually mean, in practice? Most of my self-harm has been in situations that were overwhelming not emotionally, but cognitively, and in which I couldn’t just give up and stop trying to think or to process what was happening. Usually this happened at school. “Let’s split up into small groups and work on these problems” led to so many people talking at once that I couldn’t think, which led to me scratching my arms with my fingernails under the desk.
If I had to put an emotion word to it, it would be frustration. I knew I could do the work that was in front of me if I weren’t so distracted, and I was trying to make myself focus. I self-harmed for the same reasons that you press the buttons extra-hard when your computer isn’t working, for the same reasons that you clench your teeth and hold your breath while trying to lift something heavy. I was trying very hard to make my body and mind do something that they aren’t good at doing.
If you want to read other perspectives on this, this post (which I also linked to above) has a collection of statements from autistic people about personal experiences with self-harm.