There's no question in my mind that untreated ADHD leads to drug abuse in a lot of cases. The impact that it has on your life when you didn't catch it early enough can be huge and can leave scars mentally. It's not just the meds that are important it's learning coping skills that so called normal people seem to have and ADD people don't. Like me for instance, I've never been able to plan or delay gratification, life has always been now now NOW! I've recently realized the impact this kind of thinking has had on my life over the long term, I can easily see why I turned to drugs with such maniacal devotion at the age of fifteen.
I have no regrets about it but it is something that people need to be more aware of. Treatment can help a ton yet will not solve all the problems, and we're all humans anyway and prone to making mistakes. But when you're an ADD human your are often outcasted in subtle ways due to your "inability" to get your shit together. I mean now that I take Ritalin as prescribed everyday I feel like I can wake up everyday and have a direction, plans, goals and I can follow through on them. I can see a future where I couldn't before. I no longer need to risk my life trying to find stimulation just so I can feel alive. It's not just the Ritalin, I've learned a ton about the disorder over the past year or so.
I remember when the Ritalin first really started to work after taking it daily at the same dose for a week or so, I remember thinking to myself "this is the feeling I used to get after smoking weed and drinking five cups of coffee but without the jitteriness or paranoia!" I know that I smoked pot as a way of self medicating ADD but oddly enough I prefer my Ritalin to pot now. Clarity of mind is so very valuable to me now after years of being always messed up on something.
I did have a good time experimenting along the way though, there's no real point in dwelling on what could have been if it had been caught earlier. I'm just saying people should be aware of ADHD and realize that it is very real and has very real consequences in peoples lives. Good thread, most of my friends who do drugs excessively have been diagnosed with ADD or probably should be since too many of them truly think they are just too dysfunctional to contribute to society in a meaningful way.
Undiagnosed/treated ADD can be very devastating, especially since it only gets worse as you grow older, the added responsibilities that you have to deal with as an adult, stress, people's ignorance of the disorder only makes the undiagnosed adult even worse off than they were.
There is also a good side to ADD, ADD people can be exceptionally creative and intelligent people that are very intuitive and innovative. The more people can harness the good sides of ADD the better. Society needs ADD people, most of the music and art and literature we all love was created by people who lived their own way, being able to follow your inner rhythms while tuning out the "accepted" way of living is actually considered an ADD trait. Many of the great inventors and innovators probably had/have ADD, but if you can find your niche' you can really make it work for you without ever setting foot in a psychiatrist's office.
Sorry if this is too long, it just really hit home with me and my life experiences. My ADD diagnosis changed my life completely and I'm currently cleaning up some of the wreckage from my wreckless past.
who knows... ty for your thoughts on the matter maser yoda. Now be safe on the wet roads .. 
... nice n sketchy huh, what can you do man. I hope the best for him but he loves to go up uP UP and away.