i have a pearler!
my son too is ADHD, hes 16 now.
When he was a baby he had no concentration, by the time he got to 3 it was pretty obvious that there was a problem. It took about 7yrs for a diagnosis - incidentally i was offered ritalin BEFORE dx! DS1 has never been medicated as we felt it wasnt right for him.
By the time he was 8, i could have mercilessly put his head thru a wall!!! , but managed not to - however the dentist had to offer me night protection for my teeth-grinding. some months his behaviour was horrid, and some months worse!
Strategies helped - grab ANY help with both hands, keep calm at all times (as it just made him worse if i got agitated), cut out all additives, ONLY ONE instruction at a time (and wait for processing of that instruction) and invest in a personal DVD player!
DS1 was taken out of school in yr5 (not an option for everyone) but it decreased his agression and frustration 100%, it was SOOOOOOOOO hard, but it was worth it.
He is now 16.... he has a lively sense of humour, is kind, willing, polite, helpful, and NICE! he is a lovely person to be with. OK his topic of conversation is a little dull, and he has some very strange ideas, still very impulsive, and quite 'young' for his age. BUT he is a happy, lovely person... and i really couldnt have imagined being able to say that 5yrs ago.
As for drugs and the like - he understands that his brain isnt quite the same as others, and if he eats the wrong thing (coloured sweets, coke) then it sends him 'wappy' and he can feel it happening. He understands that drugs would have very much more greater undesired effects and is accepting that i couldnt tell him what would happen, but more than likely it wouldnt be good. Hes not interested in alcohol (same reasons) and doesnt feel ready to broach the whole 'girls and sex' subject - as i said, hes very young. But when hes ready im more than happy to chat if he wants.
SO, its not all doom and gloom at all. There are some lovely people who happen to be ADHD, and while a lot do have obsessive/additive personalities - many can be channelled in the right direction - theres a lot that dont either!
PS i once read that " children with ADHD come from 'broken homes'" i remember thinking, "aye, its them that broke em!" Make sure you get the suppoet from ALL family members. {{{HUGS}}} for your journey.