Dirt-common, I'd say. -
But in a different context.
Repetitive behaviors in themselves as
a method for self-calming are quite common for autistic people. - Particularly stimming. Pacing back and forth and swaying while remaining stationary are my primary stims. And that stims reflect
a positive way of autistic people dealing with things. Conversely there's nothing particularly positive about OCD as a comorbid condition to autism.
I was diagnosed with social anxiety, OCD and chronic clinical depression in 1982. I look at my OCD behaviors as most definitely not something related to stimming, or any other perceived method of self-calming. That they do quite the opposite. Involving negative thoughts, reactions and rituals that inevitably occur and reoccur over and over. And that for some, cognitive behavioral therapy (CBT) work to help one to alleviate overcome such things. For others like myself, CBT simply failed.
As for "hearing voices", I see that as something apart from basic considerations of autism or OCD. Something that I have never experienced, such as schizophrenia.
https://www.verywellmind.com/the-relationship-between-autism-and-schizophrenia-6748936