These studies may also miss categorize heavy/habitual users. Heavy canabis use tends to leave a somewhat functional if unmotivated individual. This is in contrast to heavy alcohol users who quickly lose the ability to function in society due to hangovers and inebriated actions.
There are some surprisingly functional heavy drinkers. People who consume alcohol throughout the day rather than just at night can largely avoid hangovers and end up with incredibly high tolerance levels.
You don’t want them to operate heavy machinery, but for rote tasks that don’t take a lot of coordination it can be hard to tell.
