“…The World Health Organization adherence model posits that adherence is determined by the interplay of ve sets of factors: social and economic (e.g., age, ethnicity, education), health care system (e.g., type of insurance), condition-related (e.g., duration, comorbidity), therapy-related (e.g., type of medication, complexity of regimen, side effects) and patient-related (5). Factors most often studied are social-economic and patient-related, as the rst is easier to measure and the latter is considered as potentially modi able in interventions, including perceptions on illness, medication beliefs, habits in medication and affective states (11,12). Most studies on adherence among PwMS examined the social-economic factor and only few studies investigated patientrelated factors (13)(14)(15) or therapy-related (2,(16)(17)(18).…”