Tehran University of Medical Sciences Journal of Sleep Sciences 2476-2938 2 1-2 2018 02 13 34 39 EN Mehdi Madanifard Department of Psychology, School of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Mehrdad Mazaheri Department of Psychology, School of Psychology, University of Sistan and Baluchestan, Sistan and Baluchestan, Iran Imanolah Bigdeli Department of Psychology, School of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran 2017 06 12 2017 08 20 Background and Objective: The main aim of the current research was to compare sleep problems in two groups of patients with addiction treated with preservatives substances (i.e., methadone and buprenorphine). Materials and Methods: Two groups of addicts (30 patients treated with methadone and 30 patients treated with buprenorphine) were voluntarily selected using an available sampling method and were asked to complete Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), Insomnia Severity Index (ISI), and STOP-BANG question-naires. Data analysis was performed using independent t-test and descriptive indicators at the significant level of 5%. Results:The average age was 39.16 ± 5.07 in the methadone group and 40.30 ± 6.17 years in the buprenorphine group (P < 0.050). All participants were male. Current findings indicated that significant difference existed between the two studied groups in the PSQI (P < 0.001) and ESS (P < 0.010) with the higher mean score for the methadone group. However, buprenorphine group showed higher mean score than methadone group on the ISI and STOP-BANG and the-se differences were found statistically significant (P < 0.010). Conclusion: Sleep problems may be one of the reasons for the failure in the treatment of addiction among patients with addiction. https://jss.tums.ac.ir/index.php/jss/article/view/68