Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 13 3 2018 06 14 184 190 EN Mohammad Bagher Saberi Zafarghandi Addiction Department, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran. Hamid Khanipour Institute of Educational, Psychological and Social Research, Psychological Studies Group, Kharazmi University, Tehran, Iran. Seyed Mojtaba Ahmadi Department of Clinical Psychology, School of Medicine, Student Research Committee, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2017 02 26 Objective: Individuals with substance use disorder are not homogeneous as we might regard. Thus, this study was conducted to present a novel classification of substance use disorder based on temperament, addiction severity, and negative emotions. Method: In this correlation study, Temperament and Character Inventory, Addiction Severity Index, Aggression Subscale of MMPI-2, Depression, Anxiety, Stress Scale, Emotional Schema Questionnaire, and Psychosocial Checklist were used for data collection. Results: The cluster analysis of 324 individuals with substance use disorder explored 4 subtypes. Subgroups were named based on the main features as emotionally distressed, constitutional, nonconformist, and impulsive. Significant differences were found among groups in emotional schemas, history of mental disorder in the family, rate of relapse, and history of imprisonment. Conclusion: It seemed that temperament dimensions, addiction severity, and negative emotional states were valid components in classifying individuals with substance use disorder. https://ijps.tums.ac.ir/index.php/ijps/article/view/977 https://ijps.tums.ac.ir/index.php/ijps/article/download/977/736