IRCT20220711055435N1 IRCT 2023-05-29 University of Social Welfare and Rehabilitation Sciences Investigating the effectiveness of a brief intervention for alcohol and drugs linked to the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) on reducing substance use Investigating the effectiveness of a brief intervention for alcohol and drugs linked to the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) on reducing substance use among 15- 18 years old drug users 2023-05-22 anticipated 54 Complete https://irct.ir/trial/64720 interventional Randomization: Randomized, Blinding: Not blinded, Placebo: Not used, Assignment: Other, Purpose: Supportive, Randomization description: In this research, simple randomization will be done by role of a die method for each person and they will be placed in one of two groups (intervention and control). N/A substance use. Intervention 1: Intervention group: The Intervention group will receive ASSIST short-term intervention services in addition to usual services. The time required to implement the intervention for each person is 5 to 30 minutes, but it seems that in this research, at least 20 minutes of time is needed to implement this intervention. Three months after the intervention, the ASSIST screening test will be taken again (post-test) and the scores obtained in the pre-test and post-tests will be compared. Intervention 2: Control group: The control group will only receive the usual services at Yaran Danesh and Mehr Association, but will be tested twice in three months. Undecided - It is not yet known if there will be a plan to make this available Justification or reason for indecision in sharing IPD is If the supervisor approves, a decision will be made about its publication.