Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 3 1-2 2019 01 07 25 29 EN Mehdi Madanifard Department of Psychology, School of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Mehrdad Mazaheri Department of Psychology, School of Education and Psychology, University of Sistan and Baluchestan, Zahedan, Iran Imanolah Bigdeli Department of Psychology, School of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran 2017 12 09 2018 04 09 Background and Objective: Sleep disorders are one of the problems of substance abusers, which might result in emotional and logical thinking breakdown in those individuals. The main aim of the current research was to compare sleep problems in two groups of substance users and normal subjects. Materials and Methods: This study compared 90 substance users who were referred to the addiction treatment centers with 90 subjects who were relatives as a normal group. Participants were asked to fill out Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), and STOP-BANG questionnaires. Data analysis was performed using independent t-test and descriptive indicators at the significant level of P < 0.050. Results: The average of age was 38.21 ± 4.35 years in the addict group and 41.11 ± 5.27 in the normal group (P < 0.050). All the participants were men. Our findings indicated a significant difference between the two study groups in the PSQI (P < 0.001) and ESS (P < 0.010) scores with a higher mean score for the addict group. However, normal group showed a significantly higher mean score on the ISI and STOP-BANG compared to the addict group (P < 0.010). Conclusion: According to the results of this study, sleep problems are common in people who are dependent on drugs, and should be given more attention. https://jss.tums.ac.ir/index.php/jss/article/view/91