You have gotten many answers already, but here is my story. My son has obsessive behaviors from how many paper towels he uses to a restricted interest, which unfortunately is toilets. He draws toilets, talks about toilets, pretends objects are toilets, etc. It used to be clocks and we used to jokingly call him Flavor Flav (MTV character who wore a huge clock necklace). He is only 5, but I have always been convinced he has Autism or Aspergers. He's a very smart kid, but struggles socially b/c of his obsessions. He also flaps and was developmentally delayed. I told doctor after doctor that I was concerned that he had Autism and no one would listen to me. I finally got him into a wonderful OT who listened to me and agreed there was a reason to believe he may have something going on. He was diagnosed with Pervasive Developmental Disorder Not Otherwise Specified (PDDNOS). I'd neer heard of it before and Autism belongs to a group of disorders called Pervasive Developmental Disorders, so there is 5 categories: Autism, Rett Syndrome, Childhood Disintegrative Disorder, Asperger Syndrome, and PDDNOS. Anyway, PDDNOS is the other category when they show some, but not all of the characteristics. I never knew about this before, but I was just glad to get someone to listen to me; I felt like they acted like my concerns were not valid. It is SO hard for me dealing with the restricted interest and redirecting him to another activity. Unfortunately toilets are EVERYWHERE and so it's a constant battle w/people looking at me like I'm crazy when I won't take my young child to the restroom when he is requesting to go. Perhaps your son has OCD or PDDNOS? Despite what you find out I just want to wish you the best of luck. It is SO hard dealing w/an intense, pervasive obsession with something.