On therapy I've seen people who did all kinds of drugs for decades. There was even a guy who was 60 years old. First cig at age of 7, first joint on age of 9 (he mistook it with a cig when he stole it) and he continued that way. He did meth every day for the past 30 years. He took cocaine for parties. That way he didn't feel the effects of alcohol and could drink much more than usual. Then to calm down and to be able to sleep he took marihuanna and Benzo's (I think it's called Z-drug in english? Anyway. It's basically painkillers.). Acid on special ocasions like festivals and all other kinds of stuff I've never even heard of before.
Most eloquent person I've ever seen.
I'm not denying that drugs are bad and make your brain freak out. Another person who was 34 and did meth for the past 20 years had weird twitchings all the time. Everyone responds different to each drug and saying you can't form a sentence after 10 years of consuming, you're just completely overestimating drugs (which is a good thing. But the arrogant way you expressed it was no good).