• Whenever a substance abuse treatment program and a mental illness treatment program decide to join forces, the collaboration will have a greater chance of success if they are located close to each other. In fact, as the report points out, "Programs enjoyed more success when staff, clients, and treatment areas were geographically close together. They were least successful when staff and/or clients had to travel to different locations for various services—even when they were merely on different floors of the same building."