Please consider the suggestions by the others that have posted on this issue and steer clear of the Ritalin.  I had been told when my 5 year old CAH child was 2 1/2 and "acting out" that he was a prime ADHD candidate......AT 2?!?!?!?!?!?!?!?!  And by his endocrinologist at the time!!!!  Needless to say, I changed doctors.  My son is now almost 6 and in Kindergarden and doing very well.  I had even mentioned this "prime candidate for ADHD" thing to his teacher and she was disgusted.  I would definitely explore the non medical alternatives to treatment and perhaps even get a second, unbiased opinion from another professional.  The last thing our children need is to have to worry about taking anti-depressants for goodness sake.  Good Luck to you!!!!