What would you personally look for as a sign of sobriety?

This question is intended for people with direct personal knowledge of someone who uses drugs.

Not alcohol and not weed but things like designer drugs. Research chemicals. Benzos. Weird stuff.

Field sobriety tests are practically useless. Law enforcement can test BAC but not much else.

If someone tells you he’s sober, and you don’t think so, what do you consider telltale signs of intoxication? or what would be evidence of sobriety?

If you know, you might prefer to answer privately. That’s fine with me. Thank you.

 
Tags as I wrote them: drugs, intoxication, sobriety, field tests, stoned, chemical dependency.