I read the response you provided below while doing some research for my 12 year old son.  We relocated from Florida to Indiana 18 months ago, 7-8 months ago it was recommended that he take allergy shots......additionally around August he was put on other medications for his allergies (which are severe).  He was on Singulair and Allergy DN II......we noticed a couple of months ago that he was not behaving normally.  He developed "habits" but they were obsessive, he said that if he didn't do certain "rituals" three times that he was afraid something would happen to one of our family.....we took him to a child phychologist, but about the same time I started researching possible causes and found info about Singulair.....I called his allergist, explained his symptoms and he said to take him off the Singulair immediately, which we did.  The "bad thoughts" went away, but he still has these habbits (rituals) that he doesn't seem to be able to break.  My question.....is it possible that the Allergy DN II or the allergy shots are causing this problem.......we are desperate to help our son and would greatly appreciate any guidence.