This sounds like it could be PANDAS to me. My daughter has this. It has components of OCD, ADD and aggression, but is not caused by a chemical imbalance like those things can be. It is caused by a common strep infection (or sometimes a virus.) Before you stop reading and say, oh but he has not had a sore throat, please read on...
It is an autoimmune disease that often has NO symptoms other than the psychiatric ones. Often the child will not have a sore throat or any indication that they are sick- this is because the body is not recognizing the strep in a "normal" way and is instead attacking ITSELF, causing the brain stem to swell and the behaviors to flourish.
Since it is an issue with brain swelling, you see it manifest in a variety of ways, but here are some common themes:
-OCD which is different in children than in adults. It can be anything from the child getting upset because you don't do something EXACTLY the right way, to asking you to repeat a word a million times over, to having to have ONLY the blue toothbrush, etc. This can range from mild to VERY extreme.
-Bed and day-wetting problems, or issues with not wiping or wiping too much. More common in girls (and obviously you would see the regression in a child who is potty trained, not one still in diapers, etc.)
-Regression in other areas- babytalk or made up languages, drawing or handwriting is changed, slanted strangely compared to usual, crowded in margins, or has regressed (stick figures versus more elaborate drawings, etc.)
-Randomly not knowing how to do something they have always done. This can be anything from tying shoes and suddenly one day not knowing how (and frustration ensues) to being almost catatonic and not understanding how a doorknob or shirt works. This will look like deliberate, willful disobedience or the child ignoring you.
-Enlarged pupils and a "wild" look- like a switch was flipped suddenly. Pupils will often remain enlarged for days, weeks.... The wild look can come seconds before a rage attack on a thing or person, and then often it fades just as quickly as it came on.
-Not remembering the aggression, or apologizing for it and begging for help. We have personally run the gamut from her going limp afterward because she is totally physically spent, to apologizing and begging us for help, to her not even knowing anything happened. We suspected seizures but have had numerous EEGs to rule those out. It is creepy when it happens!
-Sensory issues. This can range from problems sitting still, to being overly loud, to being sensitive to sunlight and mildly loud noises, to not being able to have seams in socks. A lot of kids will SEEK sensory input and rock, spin, run around, hit things, have to touch something rough or smooth, roll on the floor, like to swing, etc.
-Tics or Tourette's Syndrome. Some kids will have something as simple as a repeated sniff that looks like allergies, or eye-blink and some will have big motor tics like shoulder shrugging. Some have none, but it's a common factor. Onset of this seems to be more around 7 yrs old, however.
If any of this sounds familiar, then I would suggest posting to the PANDAS support forum and trying to get an appointment with Dr Kovacevic (in Oak Park) who is the best (and maybe only) PANDAS dr in our area. In the mean-time, get to a pediatrician and ask for a throat culture (a quick strep swab AND demand a 72 hour culture as well.) This will give you info for Dr K but not necessarily prove anything. There is NO definitive diagnostic (blood) test at this time. The preventative for the autoimmune malfunctions and the rages are antibiotics or in some cases, IVIG (a blood-product infusion given by IV.) IF he does test positive on the throat swabs, you can go ahead and get him on antibiotics quickly to help his body calm down in the meantime until you can get in with Dr K.
If you have ANY questions, please don't hesitate to ask me or ask on the PANDAS board. For some reason, ages 3-4 seem to be the time these particular kids go from quirky to really starting to rage- maybe the brain swelling has just gotten to be too much by that point. This is NOT a fatal disease, but it can involve the heart (with Kawasaki disease) if left untreated, so it's best to rule it out.
Here are some sites for you.
The PANDAS
http://www.latitudes.org/forums/index.php?s=a7bf0ccd1dc89...
Dr K's website:
www.webpediatrics.com
And more information and case histories:
www.pandasnetwork.com
My blog with some of our story is here:
www.chickiepea.wordpress.com
-M.