2The Matrix Intensive Outpatient Treatment for People With Stimulant Use Disorders (IOP) pack-age provides a structured approach for treating adults who abuse or are dependent on stimulant drugs. The approach followed in the treatment package was developed by the Matrix Institute in Los Angeles, California, and was adapted for this treatment package by the Knowledge Application Program of the Center for Substance Abuse Treatment of the Substance Abuse and Mental Health Services Administration (SAMHSA).The Matrix Intensive Outpatient Treatment for People With Stimulant Use Disorders (IOP) pack-age provides a structured approach for treating adults who abuse or are dependent on stimulant drugs. The approach followed in the treatment package was developed by the Matrix Institute in Los Angeles, California, and was adapted for this treatment package by the Knowledge Application Program of the Center for Substance Abuse Treatment of the Substance Abuse and Mental Health Services Administration (SAMHSA).