@boomerang,
T has worked with juvenile populations, including drug offenders.
The refrain she got over and over again from the kids was, "why didn't someone tell me how dangerous drugs are? I tried ecstasy [or meth, or cocaine, or whatever] one time, and now I'm effectively brain damaged."
These drugs can burn out the neurotransmitter receptors, which basically fries your brain.
Doesn't happen to everyone, but it happens to a lot of them. And there's no way to know if it's going to happen ahead of time.
It's like playing Russian Roulette with the rest of your life.