Introduction
Multiple sclerosis is a demyelinating disease of the central nervous system, and one of the most common neurological diseases in humans. One of the most important symptoms of MS is pain, which leads to a low quality of life, increased disability, and decreased mental health. One of the positive pain coping methods is the pain self-efficacy, which refers to a person’s belief in his ability to participate in certain activities and achieve goals despite the presence of pain caused by the disease. Improving self-efficacy can increase life expectancy and improve health behaviors. It is also associated with the management of physical and mental complications in patients with chronic disease. On the other hand, pain catastrophizing is common in people with MS. Pain catastrophizing is a maladaptive cognitive, emotional response to pain that includes a tendency to ruminate, magnify the threat, and feel helpless against pain. Individuals with less pain catastrophizing are more likely to adapt to the disease. 
Conventional drug therapy is not enough for MS patients and often has side effects. compassion-focused acceptance and commitment therapy (CFACT) is a combination of two approaches: acceptance and commitment therapy (ACT) and compassion-focused therapy. The ACT is one of the non-pharmacological methods introduced by Hayes et al. The purpose of this approach is to help clients create a rich and meaningful life so that they know their values and goals and stand for them in life. Self-compassion was first proposed by Neff, but it was Gilbert who used this construct in therapy sessions and proposed the compassion-focused therapy (CFT). 
Despite the increase in the number of MS patients in recent years, especially in Iran, less attention has been paid to psychological interventions for these patients. To our knowledge, no research has yet been conducted on the effectiveness of ACT and CFT on pain self-efficacy and pain catastrophizing in patients with MS. Therefore, this research aimed to investigate the effectiveness of CFACT on pain self-efficacy and pain catastrophizing in patients with MS.

Methods
This is a randomized controlled clinical trial with a pre-test/post-test design. The study population included all MS patients in Mazandaran province, Iran, during 2022-2023, of whom 36 patients were selected by voluntary sampling method and randomly assigned to two groups of 18 including intervention and control. Diagnosis of MS by a neurologist, having MS for more than one month, higher than middle school education, no psychotic disorders, and no history of hospitalization were the inclusion criteria. Absence from more than two treatment sessions, unwillingness to continue participation in the study, using psychoactive drugs during the sessions, and the recurrence of the disease were the exclusion criteria. The disability of patients was measured by Kretzke’s expanded disability status scale. They completed the pain self-efficacy questionnaire (PSEQ), and pain catastrophizing scale (PCS). A 10-session therapy protocol was used for intervention, adapted from the book “ACT Practitioner’s Guide to the Science of Compassion”. Each session lasted for 90 minutes, and the sessions lasted about two and a half months. Finally, the data were analyzed using SPSS v.27 software and multivariate covariance analysis. To analyze the difference, the multivariate analysis of covariance (MANCOVA) was carried out.

Results
The mean scores of the study variables in two groups are shown in Table 1.


Based on the results in Table 2, CFACT had a significant effect on at least one of the variables (F=7.07, P<0.05) in MS patients.


The results of MANCOVA showed that the CFACT increased pain self-efficacy (P=0.004) and reduced pain catastrophizing (P=0.025) in the intervention group compared to the control group at the posttest stage (Table 3).


The effect size for pain self-efficacy and pain catastrophizing was 23% and 14%, respectively.

Conclusion
The CFACT can increase pain self-efficacy and reduce pain catastrophizing in patients with MS.  It can help patients shift their focus from catastrophizing pain to engaging in meaningful activities that align with their values. This treatment can be used in clinics and hospitals.

Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of the University of Mohaghegh Ardabili (Code: IR.UMA.REC.1402.029), and was registered by the Iranian Registry of Clinical Trials (Code: IRCT20240217061032N1).

Funding
This article was extracted from a master’s thesis in General Psychology, funded by the University of Mohaghegh Ardabili.

Authors contributions
Design, conceptualization, project administration, data collection, data analysis, writing the original draft, and editing: Mehdi Ebrahimpour Azizi; Design, conceptualization, supervision, and review: Nader Hajlo and Mohammad Baghbanian; intervention: All authors.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgments
The authors would like to thank all the patients participated in this study for their cooperation, and the Deputy for Research of the  University of Mohaghegh Ardabili for their financial support.


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