When my daughter was a baby, I made jokes about how obsessive she was. I was joking, but in retrospect I realize that she has had Obsessive Compulsive Disorder (OCD) since she was an infant--probably since she was born. By the time she was 3, I was no longer joking about it. It was obvious there was something terribly wrong. Her biggest obsessions then were grooming-related. When bathing, she had to wash each body part a certain number of times and had to start over if interrupted. She washed her hands a hundred times a day and had to count while doing it; ditto with combing her hair, brushing her teeth, etc. Saying goodby to me at preschool and going to bed at night both involved hours-long elaborate rituals that had to be performed exactly right; if not, the rituals had to be started over again and again and again until she felt they were performed "right." She had lots of issues with her clothes--tags were unbearable, she couldn't wear certain materials, she couldn't wear shoes and socks. She put her clothes on, took them off, and put them on again over and over in a futile attempt to make them feel "right."
It took me a year to get a diagnosis and treatment, but at age 4 she started taking Paxil and it was a miracle drug. Her Obsessive Compulsive Disorder (OCD) was brought immediately and completely under control. I had investigated cognitive behavior therapy (which has been found to be effective with Obsessive Compulsive Disorder (OCD)), but the doctor and I both agreed that at age 4 she did not have the cognitive maturity to benefit from it, and it seemed unnecessary because the medication worked so well. Because your son is very verbal and mature, cognitive behavior therapy might work well for him. I'm thinking about it again now that my daughter is older.
Unfortunately, as the years went by (3 years since she started Paxil), her mood became very unstable and she recently suffered some really terrible episodes of mania, so we had to discontinue the Paxil. I've mentioned before that she is now taking Abilify, which has stabilized her mood, and recently started Prozac for the Obsessive Compulsive Disorder (OCD). However, she is only taking 5 mg Prozac and I don't see any benefit. I'm not sure what to do next as I am afraid to increase the Prozac--afraid that it will trigger mania. I would be really interested to hear how much you have to increase your son's Prozac to obtain a therapeutic effect.
Incidentally, I have another child with Obsessive Compulsive Disorder (OCD)--my 22-year old son. I did not know he had it (in fact, did not know what Obsessive Compulsive Disorder (OCD) was) until he was 15, which was about the time my daughter was born. I had taken him to the doctor to be treated for depression and he casually mentioned to me that the doctor said the Paxil prescribed for his depression would be good for his Obsessive Compulsive Disorder (OCD) as well. I said "What's Obsessive Compulsive Disorder (OCD)?" I found out that lots of things I thought were merely eccentricities of his personality were manifestations of his Obsessive Compulsive Disorder (OCD). His main symptoms are an extreme need for symmetry--has to "even" everything up--and a hoarding compulsion. He cannot throw anything away, as he is afraid he will need it someday, even if it is absolute junk.
I would love to hear how your son is doing--particularly if the Prozac helps and if there are any negative side effects as you increase the dosage.