Intensive Outpatient (IOP) Substance Abuse treatment is designed for clients who have severe substance abuse needs. IOP clients will attended three, three hour groups per week for groups 12 weeks. Group therapy sessions will consist of psycho-education, as well as therapeutic process. This will provide clients the opportunity to learn new skills, explore their historical pattern of substance use, and receive feedback from peers. This group will utilize the Matrix Model for Criminal Justice Settings, developed by Donna Johnson, Richard Dawson, and Jeanne Obert. Once the client has completed 12 weeks of IOP, they will step down to weekly outpatient substance abuse group therapy.