The terms ‘adherence’ and ‘compliance’ are used somewhat interchangeably in the literature, but carry different connotations.1 Whilst the former is active, the latter implies passivity of the part of the patient – that they are doing as they are told to by their doctor.1,2 Because medication adherence is not solely the responsibility of the patient, some have argued that the complexities of adherence are oversimplified by these words which can have the effect of blaming the patient.1,2 The WHO defines adherence as an active process, in which the patient is participating in an agreed behaviour:2

“The extent to which a person’s behavior – taking medication, following a diet, and/or executing lifestyle changes – corresponds with agreed recommendations from a health care provider”

References:
[1] Brown MT, Bussell JK. Medication adherence: WHO cares? Mayo Clin Proc 2011; 86 (4): 304–314.

[2] WHO. Adherence to Long-Term Therapies: Evidence for Action. 2003. Available at: https://apps.who.int/iris/bitstream/handle/10665/42682/9241545992.pdf. Accessed September 2022.

[3] Jimmy B, Jose J. Patient medication adherence: measures in daily practice. Oman Med J 2011; 26 (3): 155–159.

[4] Wolff K. Characterization of methadone overdose: clinical considerations and the scientific evidence. Ther Drug Monit 2002; 24 (4): 457–470.

[5] Mersha AG, Eftekhari P, Bovill M, et al. Evaluating level of adherence to nicotine replacement therapy and its impact on smoking cessation: a systematic review and meta-analysis. Arch Public Health 2021; 79 (1): 26.

[6] Parpouchi M, Moniruzzaman A, Rezansoff SN, et al. Characteristics of adherence to methadone maintenance treatment over a 15-year period among homeless adults experiencing mental illness. Addict Behav Rep 2017; 6: 106–111.

[7] Hollands GJ, Naughton F, Farley A, et al. Interventions to increase adherence to medications for tobacco dependence. Cochrane Database Syst Rev 2019; 8 (8): CD009164.