No, this is the old "Reefer Madness" mentality, meant to make happy both the Puritans and the prison profiteers while keeping the politicians in an elevated state of power.
What actually happens, and Portugal ran this experiment with a sample size of over 8 million people during the past decade, is that when drug use is decriminalized, the usage rate quickly falls to about half.
Most of those are people who are no longer afraid to seek treatment. Some are folks who wind up court-ordered to get treatment, and a few were drug users who were only doing it because drugs seemed cool because they were illegal.
At the end, though, the incontrovertible fact is that the community has half the number of drug users as it did under Prohibition. Prohibitionists are responsible for a doubling of the drug usage rate in the community. Does that seem counter-intuitive? So what? The data is in.