en روان شناسی تکاملی Evolutionary Psychology پژوهشي Original <div style="text-align: justify;"><span style="color:#3300ff;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:2;"><b>Objective:</b> Substance use disorder, particularly marijuana use, is associated with adverse psychological outcomes such as an increased risk of suicide and difficulties in emotional regulation. The present study aimed to determine the effectiveness of Acceptance and Commitment Therapy (ACT) on suicide risk and cognitive emotion regulation in men with marijuana use disorder.<br> <b>Methods</b>: This study employed a quasi‑experimental design with a pretest&ndash;posttest control group. The statistical population included all men aged 18 to 50 years diagnosed with marijuana use disorder (based on DSM‑5 criteria) who referred to addiction treatment centers in Karaj and Fardis in 2025 (approximately 2,000 individuals). From this population, 30 participants were selected through convenience sampling and randomly assigned to an experimental group (n = 15) and a control group (n = 15). Research instruments included the Beck Scale for Suicide Ideation (BSSI), the Cognitive Emotion Regulation Questionnaire (CERQ), and a DSM‑5 clinical interview. The experimental group received eight 90‑minute sessions of ACT, while the control group received no intervention. Data were analyzed using repeated measures analysis of variance (ANOVA) with SPSS version 22.<br> <b>Results</b>: The results indicated that Acceptance and Commitment Therapy significantly reduced suicide risk (including death ideation and active suicidal preparation) in the experimental group compared with the control group (p < .05). Furthermore, the intervention significantly increased adaptive emotion regulation strategies (acceptance and positive reappraisal) and significantly decreased maladaptive strategies (rumination and catastrophizing) among individuals with marijuana use disorder.<br> <b>Conclusions</b>: ACT, by emphasizing acceptance of internal experiences and cognitive de-fusion from hopeless thoughts, can serve as an effective intervention for reducing suicidal potential and improving emotional capacities in men with substance dependence. It is recommended that psychologists in rehabilitation centers utilize this approach to enhance mental health and prevent high‑risk behaviors among marijuana users.</span></span></span></span></div> Acceptance and Commitment Therapy (ACT), Suicide risk, Cognitive emotion regulation, Marijuana use 0 0 http://ieepj.hormozgan.ac.ir/browse.php?a_code=A-10-1161-1&slc_lang=en&sid=1 Seyed Mohammad Hossein Saeedi saeisisaeidi@gmail.com 0000-0000-0000-0000 No M.A. in Clinical Psychology, Department of Psychology and Counseling, Islamic Azad University, Tehran West Branch, Tehran, Iran. Sanaz Khamami khamami@iau.ac.ir 0000-0000-0000-0000 No Assistant Professor, Department of Psychology and Counseling, Islamic Azad University, West Tehran Branch, Tehran, Iran Negar Akbari Zargar 0000-0000-0000-0000 Yes Assistant Professor, Department of Psychology and Counseling, Islamic Azad University, West Tehran Branch, Tehran, Iran