Based on your citation - I could also say "alcohol, marijuana, cough medicine, antihistamines and (possibly) caffeine cause people to become psychotic".

While technically true, it's a bit disingenuous to make blanket statements like this without qualifying the risk don't you think?

From my position as an observer of someone who has struggled with substances for a long time, Amphetamines are the worst of that list. My friend recovers from Alcohol and cocaine fairly quickly once she stops taking them. Cannabis (CBD, specifically) calms her down - it would be a great help if she could get it regularly.

Cough medicine is bad, but it's not nearly as potent of an addicting substance as the others on the list. She's used antihistamines as a hallucinogen before, but is not really tempted by them.

If you take an excess of any chemical substance, there will be consequences. Barring an underlying latent condition, amphetamine use at therapeutic levels causes cognitive improvement in the general population with minimal risks.

You must know different people than I do if everyone you know taking amphetamines is always taking them at low-levels ;)

I know people of all kinds. People that have blown out their kidneys and livers from drinking excessively until they vomited blood. I also know people that responsibly enjoy maybe one or two glasses of wine daily and have no real health issues.

It really depends on the individual, but amphetamines are no more dangerous than legal drugs. Why is ephedrine easily available OTC but not levo/dextroamphetamine?

oh I agree completely. not to mention those nasty dangerous benzedrex inhalers. I'm all for full legalization of all substances combined with harm reduction and education.