Mamabear,

Have you looked at Tourette's as a possible cause? Tourette (TS), AD/HD and OCD are believed to be genetically related. It causes verbal tics (including spitting), behavior problems and handwriting issues. There's no cure and I think of it as an eccentricity. No biggie. Check out www.tsa-usa.org

Interestingly, the tics wax and wane so it causes inconsistent behavior.