The Washington State Screening, Brief Intervention, Referral and Treatment (WASBIRT) Program was designed to implement broad-based screening for alcohol or drug use problems in major hospital Emergency Departments in the state, to provide brief interventions to those with substance use disorders, and to refer patients with more serious disorders to brief therapy or more traditional forms of substance abuse treatment. To determine whether or not receiving a brief intervention or further therapy affects subsequent alcohol or drug use, a sample of patients was selected for a six-month follow-up interview.