Hmmmm, wonder if diagnosing him with attention deficit was closer to home than not;
http://healthguide.howstuffworks.com/facial-tics-dictionary.htm
Certain medications, such as methylphenidate (used to treat hyperactivity in children), were previously thought to precipitate tics in children already prone to the disorder. However, recent studies published do not support this notion and suggest that these
medications can be used in children with tics who also have attention deficit disorder,
which commonly occurs in the same population.