Speaking about the effect of taking drugs is in most cases, in most countries, not considered to be illegal. America especially prides itself on freedom of speech.
In order to prosecute a person, sucessfully, first of all police need to be motivated to act (and typically that occurs when there is a "victim"). Then on top of that they need to collect evidence and prepare a strong case. They then need to persuade a prosecutor that they have a case worth bringing. And then, they need to then prove their case, in Court, beyond a resonable doubt (ie if the accused can raise any doubt about the case againt him, he gets off).
A typical offence to a pro who has in the past stated he used drugs, would quite simply be "you can't prove it".
So in any case, lets assume, after all of the above, a pro does indeed get convicted of a use or posession offence. He will likely get a very small fine.
So, you can see, its really a pretty pointless exercise, especially for a "crime" that does not actually hurt anyone.
