The Morisky Medication Adherence Scale: An Overview

Dec 9, 2018 1:26:30 PM


The Morisky Medication Adherence Scale is a validated assessment tool used to measure non-adherence in a variety of patient populations. It has been verified and substantiated by numerous studies on a global scale with over 110 versions and over 80 translations.1 The tool uses a series of short behavioral questions geared in such a way to avoid “yes-saying” bias commonly seen with chronic care patients. More specifically, the wording of the questions is rearranged to prevent answers that tend to follow certain behavioral patterns. This allows the patient to respond to questions about non-adherence in a spirit of full disclosure for the clinician.

The Morisky Medication Adherence Scale, otherwise known as the Morisky Scale (MMAS-8), has proved to be a valuable resource to address adherence concerns, such as forgetting to take medications or discontinuing medications without guidance. If a patient scores higher on the scale, they are evaluated as more adherent. If they score lower on the scale, they are presumed to be struggling with nonadherence. By understanding how the patient scored on the scale, clinicians and health organizations can identify underlying issues that prevent patients from taking their medications correctly, if at all.


History of the Morisky Medication Adherence Scale

The Morisky Medication Adherence Scale has a relatively extensive history that has culminated into the widely used assessment tool it is today. Copyrighted in 2006, it has garnered increasing support since 2008 when research established the predictive validity of the tool in patients with hypertension. The study, pioneered by Dr. Morisky and his colleagues, found a significant association between blood pressure control and the medication adherence score.2 However, this was not the first time that the Morisky Medication Adherence Scale was validated in patients with hypertension. Researchers had been developing and testing the non-adherence questionnaire for years prior to its widespread use.

In 1986, a simplified four-question survey demonstrated preliminary data on how the tool could assess non-adherence and overall treatment success in a smaller sample of hypertensive patients. The study found that patients who scored higher on the scale were significantly more likely to have their blood pressure under control after 42 months. Approximately 75 percent of patients who scored high on the scale exhibited adequate blood pressure control compared to only 47 percent of those scoring lower on the the scale (p < 0.01).3

The Morisky Medication Adherence Scale, which started out as a four-item questionnaire, has since been expanded into a structured eight-question survey. While the four-item version (MMAS-4) includes elements of forgetfulness and symptom severity, the eight-question version (MMAS-8) delves into other situational and emotional aspects of medication adherence. For instance, the eight-question version also assesses non-adherence due to feelings of pressure or reasons other than forgetfulness. Research has shown benefits of using both the MMAS-4 and MMAS-8 for different applications depending on the condition being evaluated.4


Variations of the Morisky Medication Adherence Scale

Since the initial development of the tool, other variations of the tool have been tested for other conditions. One study reports the use of MMAS-8 for patients suffering from gout. While the study showed limited validity in evaluating medication adherence, it provided a way for clinicians to identify patients who had concerns about adverse side effects.5 These patients were then further educated on these side effects as well as how to properly take their medications to prevent future complications.

Another study examined the use of MMAS-8 in asthma patients. Across 16 community pharmacies, medication adherence was assessed during medication dispensing in patients older than 12 years of age. The cross-sectional study found that, as adherence improved from lower to higher MMAS-8 scores, the odds of asthma control increased almost two-fold (p= 0.027).6 Overall, researchers found a significant association between MMAS-8 and asthma control.

Other countries have also implemented variations of the Morisky Medication Adherence Scale. The Malaysian Medication Adherence Scale (MALMAS), for example, has been evaluated in Malaysian patients with type 2 diabetes. The test showed further reliability with odds of achieving glycemic control in adherent patients three times those in non-adherent patients.7 Other variations and translations of the tool have also been adapted in other countries with differing patient populations. The Morisky Medication Adherence Scale has been assessed in French, Thai, Greek, and Arabic patients where it has shown success in finding ways to combat medication non-adherence.8


Advantages and Disadvantages of the Morisky Medication Adherence Scale

While the Morisky Medication Adherence Scale has seen widespread acceptance in clinical settings, there are some advantages and disadvantages for its use. The advantage of the assessment tool primarily lies in its cost effectiveness and ease of use. Clinicians experience virtually no burden when administering the test while patients have to put in minimal effort to complete the short questionnaire. Because the tool is not invasive compared to direct monitoring of drug levels, it can provide a more convenient way to obtain adherence information in real-time. After receiving the completed assessment, clinicians can offer direct feedback and support to determine any barriers to adherence.

Similar to other self-report methods, the Morisky Medication Adherence Scale can be subject to a host of confounding factors such as recall bias (which could result in overestimation of adherence). Patients may also feel pressured to deliver acceptable responses in an effort to elicit a positive reaction from their healthcare provider. These factors can potentially interfere with the consistency of the test and skew non-adherence rates.9 Therefore, it may be beneficial to implement the Morisky Medication Adherence Scale along with other adherence tools for optimal monitoring.


Alternatives to the Morisky Medication Adherence Scale

Rising non-adherence rates have contributed to the development of different approaches such as the Morisky Medication Adherence Scale and other alternatives. Different approaches to non-adherence include tracking pharmacy fill rates, pill counts, and electronic monitoring. While these methods can produce quantifiable results that are objective in nature, they do have some caveats to consider.

Tracking medication fill rates may help measure non-adherence in some patients. However, many patients with chronic conditions may also be receiving medications from multiple physicians or pharmacies. With so many medications, some patients combine their medications in a single container or use a pillbox. This could make it difficult to track pill counts in certain patients.

While electronic monitoring may be an effective tool to assess long-term behaviors and habits affecting adherence, they also have some disadvantages. Despite their ability to track data on a daily basis, many electronic monitoring devices (EMDs) can be bulky or expensive compared to other tools. Studies evaluating the use of EMDs have also found that patients may not be using the devices consistently.10



Through identifying potential barriers of adherence, clinicians can implement solutions tailored to individual patients. Interventions to correct non-adherence include educating the patient on their medications and counseling them on their disease states. Some patients are improperly informed about their medications and may have instilled misconceptions about their overall treatment. Addressing these issues can reduce any potential stress for a patient so that they can feel empowered to improve their overall health.

The Morisky Medication Adherence Scale is a simple and effective tool to address non-adherence in patients. Despite the subjective flaws of the tool, its use has been validated by clinicians and health professionals for different chronic conditions across several countries. One strong advantage is that it can be administered electronically or at each office visit for long-term consistent evaluation. In this way, the Morisky Medication Adherence Scale can help address behavioral or situational barriers affecting medication adherence. With the availability and implementation of numerous variations and translations, it is not difficult to recognize the practical benefits of using the Morisky Medication Adherence Scale to tackle non-adherence.



  1. Morisky Medication Adherence Research, LLC. Accessed March 2022.
  2. Morisky DE, Ang A, Krousel-Wood M, Ward HJ. Predictive validity of a medication adherence measure in an outpatient setting. J Clin Hypertens (Greenwich). 2008;10(5):348-54.
  3. Morisky DE, Green LW, Levine DM. Concurrent and Predictive Validity of a Self-reported Measure of Medication Adherence. Medical Care. 1986;24(1):67-74. doi:10.1097/00005650-198601000-00007.
  4. Pedersini R, Vietri J. Comparison of the 4-item and 8-item morisky medication adherence scale in patients with type 2 diabetes. Value in Health. 2014;17(3). doi:10.1016/j.jval.2014.03.1066.
  5. Tan C, Teng GG, Chong KJ, et al. Utility of the Morisky Medication Adherence Scale in gout: a prospective study. Patient Prefer Adherence. 2016;10:2449-2457. Published 2016 Dec 2. doi:10.2147/PPA.S119719
  6. Janežič A, Locatelli I, Kos M. Criterion validity of 8-item Morisky Medication Adherence Scale in patients with asthma. PLoS One. 2017;12(11):e0187835. Published 2017 Nov 30. doi:10.1371/journal.pone.0187835
  7. Chung WW, Chua SS, Lai PS, Morisky DE. The Malaysian Medication Adherence Scale (MALMAS): Concurrent Validity Using a Clinical Measure among People with Type 2 Diabetes in Malaysia. PLoS One. 2015;10(4):e0124275. Published 2015 Apr 24. doi:10.1371/journal.pone.0124275
  8. Ashur S, Shamsuddin K, Shah S, Bosseri  S, Morisky  D. Reliability and known-group validity of the Arabic version of the 8-item Morisky Medication Adherence Scale among type 2 diabetes mellitus patients. Eastern Mediterranean Health Journal. 2015;21(10):722-728. doi:10.26719/2015.21.10.722.
  9. Gonzalez JS, Schneider HE. Methodological Issues in the Assessment of Diabetes Treatment Adherence. Current Diabetes Reports. 2011;11(6):472-479. doi:10.1007/s11892-011-0229-4.
  10. Bova CA, Fennie KP, Knafl GJ, Dieckhaus KD, Watrous E, Williams AB. Use of Electronic Monitoring Devices to Measure Antiretroviral Adherence: Practical Considerations. AIDS and Behavior. 2005;9(1):103-110. doi:10.1007/s10461-005-1685-0.

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