It's almost an opposite of Hanlon's razor: "Attribute to drugs what you could attribute to lack of sleep (or similar)". That plus physical tells are the biggest

It's almost an opposite of Hanlon's razor: "Attribute to drugs what you could attribute to lack of sleep (or similar)". That plus physical tells are the biggest indicators. In the end I wouldn't say that could give a definite evaluation if someone is using drugs or not in most cases.