Document Type : Original Article
Ph.D. candidate, Department of Psychology, University of Science and Culture, Tehran, Iran.
Assistant Professor, Department of Psychology, University of Science and Culture, Tehran, Iran.
Department of Psychology, Tarbiat Modares University, Tehran, Iran.
The prevalence of adolescents who self-injure each year indicates a public health problem requiring attention and intervention. This study investigated the effectiveness of mentalization-based treatment on negative affection and non-suicidal self-injury in adolescence. The research method was quasi-experimental with pre-test and post-test design with a control group. The study included 22 adolescents with non-suicidal self-injury selected with a snowball sampling method and randomly divided into two groups, experimental (n=11) and control (n=11) from November to January 2021 in Tehran, Iran. To collect data, questionnaires such as the Inventory of Statements About Self-Injury and the Positive and Negative Affect Questionnaire were administered. For the experimental group, mentalization-based treatment was administered in ten sessions of 90 minutes each week, while the control group received no treatment. The data were analyzed using MANOVA in SPSS software version 23. The participants ranged in age from 14 to 18 years old, with a mean age of 14.89 years (SD = 2.01). The results suggest that the mentalization-based treatment had positive effects on negative affection (p < .01, F_1.18 = 9.396) and non-suicidal self-injury (p < .01, F_1.18 = 10.048) in adolescent girls with non-suicidal self-injury (p-value < .01). The study found that mentalization-based treatment for negative affection and non-suicidal self-injury was an effective intervention for adolescents with non-suicidal self-injury aged 14 to 18.