Validity and reliability of questionnaire
The development of the TPB in patients with MS a questionnaire intended to an explain patient choices to use or not to use treatment adherence drugs was based on the instructions given by Ajzen [The conceptual framework of the validity and reliability of this study was that according to the similar study Kasper et al. [The validity and reliability of this questionnaire was approved and it was completed before the training intervention and three month after the intervention by both control and intervention groups. In this tool, those questions with Content Validity Ratio (CVR) score higher than 0.62 and Content Validity Index (CVI) score higher than 0.79 were considered as appropriate and included in the study [To verify its reliability, the questionnaire was given to 30 MS patients and its reliability was calculated as upper 0.8 using Cronbach’s alpha.