All my life I have been a SEVERE nailbiter .I don’t ever remember not doing it at least . And I’m not a young person . I do it when anxious but also when relaxed , like reading or TV watching. Recently I read an article in the Guardian about adults who are realizing they have autism when their children are diagnosed , and I wondered if that’s the reason for my nail biting. I saw myself in some of the other traits listed.