You touched on a number of things there.
First of all, the treatment centre is old and outdated. If I were to design the perfect treatment environment, it wouldn't look at all like the treatment centre does. It would be a modern building, purpose-built for providing treatment. There would be treatment rooms on the units. There would be a much less prison-like environment, a more hospital-like environment.
One of the advantages, though, of having a treatment centre separate from the mainstream institutions is that you have much better control of what goes on inside the building. When I was heading up the sex offender program, every year or so we'd have a couple of guys who would actually quit the program prematurely because they couldn't get access to drugs. So if you have a treatment centre where you've got a sort of isolated population, you've got much better control over those sorts of things. They're less able to transport drugs. Drugs are more easily detected and removed from the population. So having a separate environment in which to provide treatment is the ideal situation.
The concurrent disorders program I was talking about is a program that's designed to treat the mental illness at the same time as you treat the substance abuse problem. Substance abuse actually is a diagnosable mental disorder. It's not a behaviour problem. It's a psychiatric problem, so to speak. So treating the two concurrently is much more effective than treating them separately, because the problems interact with each other. People use substances because of their mental illness, and the mental illness is made worse by the substance abuse. So treating them together, you have a much more effective intervention.