I will admit, I didn't think it through super deeply, but I have a very simple (and possibly naive) proposal.
We separate them legally the same way we separate alcohol use vs. alcohol abuse. The consequences of getting caught for speeding vs. getting caught for speeding while under influence tend to drastically differ in magnitude, so I suggest we do the same for other kinds of drug abuse.
Being under influence shouldn't be a mitigating factor while committing crimes, but for non-driving offenses it often ends up being such. So I suggest we treat it the same way for violent crimes as we do for driving offenses.
We separate them legally the same way we separate alcohol use vs. alcohol abuse. The consequences of getting caught for speeding vs. getting caught for speeding while under influence tend to drastically differ in magnitude, so I suggest we do the same for other kinds of drug abuse.
Being under influence shouldn't be a mitigating factor while committing crimes, but for non-driving offenses it often ends up being such. So I suggest we treat it the same way for violent crimes as we do for driving offenses.