en Physiology Physiology پژوهشي Research <span style="font-size:11pt"><span style="line-height:normal"><span sans-serif="" style="font-family:Calibri,"><b><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Introduction</span></span></b><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">: Addiction is a chronic disease leaving deep social, psychological, physical, and economic effects on the individual. This study aimed to assess the effects of acceptance and commitment therapy on suicidal thoughts, sensation seeking, and distress tolerance in substance users.</span></span></span></span></span><br> <span style="font-size:12pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:10.0pt">Materials and Methods</span></b><span style="font-size:10.0pt">: This was a quasi-experimental controlled trial with a pretest/posttest design. The study population consisted of all substance-dependent individuals who were referred to the addiction treatment center of the psychiatric department of Mustafa Khomeini Hospital in Ilam in 2022. Using the convenience sampling method, 32 individuals were selected as the sample population and were randomly assigned to two groups of 16 individuals. In this study, the Sensation Seeking Scale (SSS), Beck Suicidal Ideation Scale (BSSI), and Distress Tolerance Scale (DTS) were used to collect data. The data analysis method was descriptive and inferential statistics<strong>.</strong> Data were analyzed using Chi Square, Pillay effect, Wilks&rsquo; lambda, Hoteling effect, Root Largest Rey, and multivariate covariance (MANCOVA) tests in SPSS v.16, with a significance level of 0.001.</span></span></span><br> <span style="font-size:12pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:10.0pt">Results</span></b><span style="font-size:10.0pt">: Acceptance and commitment therapy was effective on the studied variables. The findings of this study showed that acceptance and commitment therapy reduced suicidal thoughts (P < 0.001), reduced sensation seeking (P < 0.001), and increased distress tolerance (P<0.001).</span></span></span><br> <span style="font-size:11pt"><span style="line-height:normal"><span sans-serif="" style="font-family:Calibri,"><b><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">Conclusion</span></span></b><span style="font-size:10.0pt"><span new="" roman="" style="font-family:" times="">: Acceptance and commitment therapy has positive effects on suicidal thoughts, sensation seeking, and distress tolerance in male substance users, reducing suicidal thoughts and sensation seeking and augmenting distress tolerance in them.</span></span></span></span></span><br> &nbsp; Acceptance and Commitment Therapy, Suicidal Ideation, Substance-Related Disorders 1 10 http://jbrms.medilam.ac.ir/browse.php?a_code=A-10-157-9&slc_lang=en&sid=1 Sajad Sohrabnejad sohrabnejad1989@gmail.com 10031947532846007308 10031947532846007308 Yes Department of Clinical Psychology, School of Medicine, Ilam University of Medical sciences, Ilam, Iran. Marzia Mehrabaninasab 10031947532846007309 10031947532846007309 No Department of Psychology, Faculty of Education and Psychology, Shahid Chamran University of Ahvaz, Ahvaz, Iran. Hassan Nazari hassan.nazari@gmail.com 10031947532846007310 10031947532846007310 No Department of Psychology, Faculty of Education & Psychology, Islamic Azad Ilam University, Ilam, Iran. AliMohamad Sohrabnejad sohrabnejad2014@gmail.com 10031947532846007311 0009-0000-3542-8662 No 4Department of Persian Language and Literature, Farhangian University, Ilam, Iran Golestan Nazari nazarigoulestan193@gmail.com 10031947532846007312 10031947532846007312 No Department of Counseling, Farhangian University, Ilam, Iran