Placebo Effect

Two young lads, about eighteen or nineteen who were passengers in the taxi today had had a drop or two to drink but were polite and well behaved.
They had a bit of a run around calling at a house to get changed and the grog shop for more beer, but the last port of call before I dropped them off threw me a bit.
They asked to stop at a shop that sold amongst other things tropical fish supplies.
They both dashed in and within fifteen seconds come out again swallowing some of the "other things" that the shop specialises in.  Legal highs, plant food, bath salts call it what you will but it's what a heck of a lot of the younger generation are gleefully consuming.
Now to me the way these two jokers started acting really weird after a maximum of maybe two minutes of necking this unknown white powder could have had one of two explanations.
The first is that this magic space dust works as soon as it hits your tongue and somehow you are in nirvana within seconds.
The second and the more plausible explanation to me is that maybe some of the effects are psychological a bit like giving a four year old wine gums and telling them that it will make them drunk.  The placebo effect they call it, all in the mind. But seriously if they are going to consume this mystery crap shouldn't the people who supply it take the time to check that they know the effect it will have on them and how long it will last and what the risks are. 
Or maybe it's all a bit of a magical mystery to them, but what the hell it sure keeps the money rolling in for them.