Hard to say at this point. We talk a lot about controlling anger, conquering addictive tendencies, etc. but the real test is when they get out.
Drugs are everything. I'd say 90% of these guys are in prison because they were addicted to drugs of various kinds, and it wrecked their lives as they grew desperate to support their habit. Master the drugs, you master the crime.
How much of the drug taking was due to some other ill that isn't being addressed? Eg, were they draw to drugs because of high unemployment, poverty, loss of hope?
In fact, I teach a class every week to 33 prisoners, inside the prison itself. Rehabilitation is absolutely the goal.