I have been doing a little research into why the anti-histamine that Monster Man is on has been helping so much with his rage. Someone on the TSA Facebook page had recently mentioned that her doctor said there was a histamine-connection to Tourette Syndrome. I am posting links to some articles on the subject that help to explain this connection. To me, it offers more explanation as to why an anti-histamine has been so successful at controlling Monster Man's rage and bringing down the number of episodes he's been having at times when they'd otherwise be at their worst.
Potential Role for Histamine Identified in Tourette's Syndrome
Abnormalities in Brain Histamine may be Key Factor in Tourette Syndrome
A Surprising Clue to Tourette Syndrome