adherence is subdivided into 2 main categories: primary adherence and secondary adherence. Primary adherence is a discrete event that assesses whether or not the patient received the first prescription. In contrast, secondary adherence is an ongoing process that measures whether or not the patient received dispensings or refills as prescribed during a defined observation
period. Only after these adherence subconstructs have been acknowledged and assessed can the next level of secondary adherence—whether it is adequate or inadequate be assessed. In these proposed definitions, the converse of each adherence term is simply “non” as in “primary nonadherence” and “secondary nonadherence.”