'Drugs' is the snappy term almost everyone employs for entheogens.
An entheogen is any chemical that is distinguished for its effect on your awareness instead of on say, your endocrine system or your vascular system.
There is all sorts of debate on this so I'll be blunt for me: there are two kinds of drugs. There are drugs that are used by choice, and drugs that are not and cause trouble. Heroin and crack cocaine are two substances which merit serious attention by people who want a safe community (or their proxies).
It is my considered opinion that everything else should be left up to humans trying to make good human decisions. (Remember, I'm not saying anyone has to listen to me.) The twin phenomena of alcohol and tobacco make me twitch as I say all this, because for all the damage they've been known to cause, I think everyone knows banning either is a pipe dream.
But (in my considered opinion) banning 'anything else' is creating what Thelemists call 'artificial crime.' To expect each human to never want a thing that the culture knows causes euphoria, is unfair to how humans actually are.
Building Good Human Decisions
Anyone who is serious about 'drug prevention' needs to learn to admit three things: one, that not every drug experience ends in someone getting defibrillated; two, that they cannot control the circumstances in which their pupils, for want of a better word, will be exposed to drugs for the first time; and three, that doing drugs is fun.
The whole reason people do drugs is that it's fun. The biggest other reason is that you don't die every single time. You simply take a risk. If this risk weren't manageable, the human psyche would think about doing drugs the way it thinks about poking your own eyes out.
Explain the risks how you want, so long as you are accurate, but do not try to scare pupils for want of a better word into thinking that on their first time out, they're dead! It will not work, and anyone who tries or has already tried drugs, and lived to tell will think that you sound like a jackass, and will be less likely to consider the rest of your information.
The biggest mistake I've seen in all of anti-drug literature is to rattle off a list of negative effects and not mention euphoria.
A common if not the principal effect of nearly if not all entheogens is: feeling fucking great.
Which brings me to a kind of thesis statement:
It is safer for those who have not done drugs before, to explain what they are and why people do them rationally and clearly, so that if they choose to assume a risk they are at least doing so knowingly.
Admit that doing drugs is fun. You will get to look smart in front of your pupils for want of a better word. Because then you can credibly explain how that kind of fun, can make real life, which is amazing, look and feel like crap during a comedown: because sometimes real life just can't measure up without the feeling you still remember from being on the drug.
Profound emotional disturbance or disorientation can mess with your life in all kinds of ways in all kinds of settings or timeframes, especially if you have no kind of lucid forewarning.
You can explain how these other, subtler aspects are the kinds of things you will have to stay very aware of, if you feel you absolutely must do drugs. Or just don't assume the risk in the first place, if it frightens you or if you can't be bothered to comprehend it. Because...
now we get to move on to There can be serious consequences: you can blow a lot of money, you can cause health problems in the short- or long-term, you could run up against emotionally disturbed people or find yourself subject to prosecution. All of which is true and convincing all on its own...