My son also has AS, and I have several family members with OCD. My grandmother is so much like Monk that sometimes it feels like the character was based on her. I love this show because I have known (and loved) people like him all of my life.

I agree with you that there are a lot of similarities between OCD and AS, and I have seen an article or two speculating on the possibility that Monk has undiagnosed AS. Obsessive compulsive behavior is listed as one of the possible criteria for an AS diagnosis, and when my son was being evaluated, the doctors even asked me “Does he display any obsessive or compulsive tendencies?” and “Does he have any unusual phobias or fears?”

I have been curious whether a correlation has been found between OCD, AS and ADD, (*and PKU) because my daughter and I both were diagnosed with ADD and there are some common symptoms there as well.

*They have only recently found that there is a correlation between ADD and PKU, a very high percentage of people diagnosed with PKU also have ADD. PKU is a genetic, metabolic disorder that, untreated, leads to neurological damage and even death. I am especially interested in this because my son was also diagnosed with transient PKU soon after birth, and because PKU is diagnosed with blood tests, which makes it harder to dispute it’s existence. Most people with ADD, AS or OCD or a child with one of these three conditions have been subjected to people who refuse to believe that these conditions really exist. They believe that people who have one or more of these conditions are just using them as a way to excuse what they see as bad or inappropriate behavior or they think it’s something drug companies and doctors made up. If a real correlation could be found, maybe that can eventually find a way to test for them that is harder for the non-believers to dismiss.