Prisons are basically schools for criminals. Sticking a bunch of criminals in a big box means people end up transferring knowledge, especially relating to illegal activities in this case.
Now someone who has tried drugs for the first time or done a few minor crimes isn't exactly a master criminal but they get locked up with the murderers, rapists and sheep botherers.
Instead of trying to correct bad behaviour it's harshly punished and tries to dissuade through fear.
Now this person has a record making it very hard to integrate into society meaning that they may have to turn to crime, which they learned in prison. that's what i think though.
Thank you for sharing great article katy :)