I think that while stimming is not exactly voluntary( and you may not even notice your doing it) it can be stopped at will, or controlled if you try. Where as tourette ticks are totally invoiuntary and can not be controlled at all....kind of like muscles spasms.
Also perhaps stimming actually provides us with comfort, calmness and relaxation or release of anxieties, i don't think tourette ticks do this.
These are only my thoughts though, i don't know that much about it.
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