Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 14 2 2019 05 08 130 136 EN Maryam Sahebari Rheumatic Diseases Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Mohammad Javad Asghari Ebrahimabad Department of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Ali Ahmadi Department of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Hamid Reza Aghamohamadian Department of Psychology, Ferdowsi University of Mashhad, Mashhad, Iran Mandana Khodashahi Rheumatic Diseases Research Center, Mashhad University of Medical Sciences, Mashhad, Iran 2018 05 12 Objective: The aim of this study was to evaluate the efficacy of acceptance and commitment therapy (ACT) in the reduction of disappointment, psychological distress, and psychasthenia among patients with systemic lupus erythematosus (SLE). Method: This quasi-experimental study was conducted on 24 females with lupus who referred to the Rheumatoid Disease Research Center (RDRC) of Ghaem hospital in Mashhad, Iran. This study had a pretest-posttest control group design. The participants were randomly assigned into 2 groups of experimental and control. The experimental group was treated with ACT. Data were collected using the Beck’s Hopelessness Scale, Kessler’s Psychological Distress Inventory, and Krupp’s Psychasthenia Inventory. Results: Mean age and mean duration of illness were 37.25±4.61 and 5.12±2.33 years, respectively. The mean disappointment score and psychological distress in the experimental group were lower compared to those in control group at the post experimental stage (P<0.001). Moreover, there was a significant difference between the experimental and control groups in the mean scores of psychasthenia in the posttest stage (P<0.001). Conclusion: According to the obtained results of this study, the enhancement of psychological flexibility based on ACT positively affected disappointment, psychological distress, and psychasthenia among the lupus patients. Therefore, it can be concluded that this therapeutic approach could reduce psychasthenia in patients through clarification of the values. https://ijps.tums.ac.ir/index.php/ijps/article/view/1393 https://ijps.tums.ac.ir/index.php/ijps/article/download/1393/865