Study design and randomization
We assessed 94 patients at first but 54 patients were excluded from study; 37 patients did not meet the inclusion criteria; 12 of them withdrew from the study and 5 patients were excluded because the time of therapy sessions interfered with their working time (Consort flow diagram). Based on the formula of the sample size comparison of two means with an error of 5%, with a power of 90%, and using the results of a similar study [CONSORT 2010 flow diagram is depictedThe research objectives were explained to all the participants. Written and signed consent form was obtained from the participants. Additionally, all the participants in the study were assured that their information would remain confidential and that researchers would only report the group results of the study. The experimental group received 10 weekly sessions of group schema therapy with 90 min per session, but the control group did not receive any intervention. Schema therapy was performed by the research team psychologist who was expert in health psychology and had a certificate of specialized schema therapy courses. Both groups completed CER questionnaire during pre-test, post-test, and follow-up stages (follow-up time point was 6 months after post-test). The data were analyzed using a multivariate analysis of covariance (MANCOVA) in SPSS software (version 20).