From what I understand, it usually only takes 1 hit of meth to be totally addicted.
I understood this to be true also.. Then I went to school to become a drug and alcohol abuse counselor and learned that my understanding was not true.
Telling people things like "it only takes one hit and you're addicted" is a way to instill fear. It gives way to two possible outcomes,
1- it scares the person into never trying meth. This is a good end result.
2- they try it once and see that they were deceived by the fear tactic perpetrated by their parents, news, police, or whomever. They realize that they're not addicted. Then maybe they figure they can do it again, maybe make it a once in a while thing. Then a every weekend thing.. Then they're addicted.
Outcome number 1 has a good end result. But it's really just a lie in which the end justifies the means. The person makes a good choice not to use but it's based on a lie. Maybe they pass the lie onto their children and others in the community.
Outcome number 2 has a bad end result and just like outcome number 1, the end result is partly due to the lie that was told.
Speaking truth and giving kids accurate and truthful information would be a more effective way of preventing drug use and addiction IMO.