Intentional non-adherence is one of the major reasons why patients do not reach their therapeutic goals.

The Morisky Scales consist of two subscales, unintentional and intentional non-adherence, that are coded as four dichotomous (yes/no) variables in the MMAS-4 and seven dichotomous variables with a 5-point Likert scale in the MMAS-8.

Intentional medication non-adherence is an active decision from the patient to take their medication as prescribed. This is a process in which a patient makes a rational decision based on the benefits of medication adherence compared to risks of medication non-adherence.

​Unintentional medication non-adherence is a passive process in which the patient does not adhere to how the medication is prescribed because they forget, don’t understand, or because of poor health literacy.