> The signals people pick up from their peer groups have a much larger impact on their behavior than media ever could.

This just begs the question. Why did the peers do it? Surely you see someone clearly messed up after doing drugs. Why go in follow them? There are other mindless things you could do like play video games to achieve a similar effect.

There's all sorts of (arguably destructive/harmful) cultural behaviors that you could ask the same question about. Apparently the answer is that they are human.

I also wonder why you are so certain that video games are a substitute for drug use. Do you also not play video games?

I'd love to play, but no time to spare. I mentioned video games because the OP mentioned how peer group effects are strong. If that's the case and is a proposed explanation for opiate use, why aren't these people playing video games instead. Of course they could just be doing them both.

>Surely you see someone clearly messed up after doing drugs.

You may not start to see the negative impact of drug use until years later. By then it's too late.

People often self medicate as well in the absence of proper mental healthcare, or healthcare in general.