How unintentional non adherence was validated

Medication non-adherence is a persistent challenge in healthcare, contributing to poor health outcomes and billions in avoidable costs. The 8-item Morisky Medication Adherence Scale (MMAS-8) has become a cornerstone for assessing adherence, particularly by distinguishing between intentional (deliberate) and unintentional (accidental) non-adherence. Four of its questions—items 1, 4, 5 and 8—specifically target unintentional non-adherence, such as forgetfulness or logistical barriers. Recent academic studies have rigorously validated these questions, using innovative methods to confirm that forgetfulness is a genuine barrier to medication adherence. In this blog, we take a deep dive into the academic literature that has solidified the role of these four MMAS-8 questions, exploring how researchers have used objective measures, qualitative insights, and interventions to validate unintentional non-adherence and transform patient care.
The MMAS-8 and Unintentional Non-Adherence
The MMAS-8, developed by Dr. Donald E. Morisky and colleagues, is a widely used self-report tool to assess medication adherence in chronic conditions like hypertension, asthma, and psychiatric disorders. Its eight questions include four that focus on unintentional non-adherence:

1. Do you sometimes forget to take your medication? (Item 1)
2. When you travel or leave home, do you sometimes forget to bring your medication? (Item 4)
​3. Did you take your medication the last time you were supposed to take it? (Item 5)
4. How often do you have difficulty remembering to take all your medications? (Item 8)


These questions capture behaviors like forgetting doses, missing medications due to logistical issues, or struggling with memory, forming the unintentional non-adherence subscale. Validating these items is critical, as self-reports can be skewed by recall bias or patients masking intentional non-adherence as forgetfulness. Academic studies have tackled this challenge by integrating multiple methods to confirm the accuracy of these responses, offering a robust framework for understanding and addressing unintentional non-adherence.
Key Studies Validating Unintentional Non-Adherence
Academic literature has employed diverse approaches—objective monitoring, clinical correlations, qualitative interviews, and intervention trials—to validate the MMAS-8’s unintentional non-adherence questions. Below, we explore pivotal studies that have deepened our understanding of forgetfulness as a barrier.
1. Asthma Adherence Study (2017)
• Source: Criterion validity of 8-item Morisky Medication Adherence Scale in patients with asthma, PLOS One (2017)
• Methods:
• Pharmacy Refill Records: Researchers collected community pharmacy claims data to measure asthma medication dispensing, comparing it with MMAS-8 responses.
• Qualitative Interviews: Patients provided detailed accounts of treatment barriers, including forgetfulness, during introductory interviews.
• Clinical Outcomes: The Asthma Control Test (ACT) and Saint George Respiratory Questionnaire (SGRQ) assessed asthma control and quality of life, correlating with MMAS-8 scores.
• Findings:
• In a cohort of 208 asthma patients (mean age 56, 59% female), 37% had uncontrolled asthma, and 22% experienced exacerbations, suggesting non-adherence. MMAS-8 responses to items 1, 4, 5 and 8 showed moderate correlation with pharmacy data but weaker alignment than expected, hinting that some patients reported forgetfulness to mask intentional non-adherence (e.g., avoiding side effects).
• Interviews revealed that forgetfulness (item 1) was often tied to complex regimens, while travel-related lapses (item 4) stemmed from disrupted routines. These qualitative insights validated situational forgetfulness as a barrier.
• Significance: By combining objective (pharmacy records) and subjective (interviews, clinical outcomes) methods, this study confirmed that forgetfulness is a significant but sometimes overstated barrier, emphasizing the need for contextual probing to validate MMAS-8 responses.
2. Gout Adherence Study (2016)
• Source: Utility of the Morisky Medication Adherence Scale in gout: a prospective study, Patient Preference and Adherence (2016)
• Methods:
• Pharmacy Refill Records: The Medication Possession Ratio (MPR) measured adherence to urate-lowering therapy (ULT).
• Clinical Outcomes: Serum urate levels and remission status were correlated with MMAS-8 scores.
• Patient-Reported Outcomes: The Gout Impact Scale (GIS) and EuroQoL-5 dimension (EQ5D) captured patient perspectives on adherence barriers.
• Findings:
• In a multiethnic Asian cohort, MMAS-8 showed good reliability (Cronbach’s alpha = 0.73), but its correlation with MPR was weak (r = 0.069, p = 0.521). Patients reporting forgetfulness (items 1, 4, 8) often cited side effect concerns or psychological factors (e.g., anxiety) via GIS/EQ5D, suggesting that forgetfulness may overlap with intentional non-adherence.
• Item 4 (travel-related forgetfulness) was particularly relevant for patients with irregular schedules, validated by patient reports of logistical challenges.
• Significance: The integration of MPR and patient-reported outcomes provided a nuanced view, confirming forgetfulness as a barrier while highlighting its potential as a socially acceptable excuse for intentional non-adherence. This study underscored the value of multi-method validation.
3. Psychiatric Outpatients Study (2014)
• Source: Psychometric properties of the eight-item Morisky Medication Adherence Scale in a psychiatric outpatient setting, International Journal of Clinical and Health Psychology (2014)
• Methods:
• Qualitative Interviews: Conducted with 967 psychiatric outpatients to collect MMAS-8 responses and socio-demographic/clinical data.
• Psychological Assessments: Correlated MMAS-8 with scales like the Drug Attitude Inventory and Multidimensional Health Locus of Control to explore cognitive and attitudinal factors.
• Clinical Correlations: Adherence was compared across mental disorder diagnoses (e.g., schizophrenia, depression).
• Findings:
• Item 8 (“How often do you have difficulty remembering to take all your medications?”) had the highest factor loading (r = 0.74), indicating forgetfulness as a key barrier in psychiatric patients. Patients with higher psychological reactance or belief in chance-based health outcomes reported more forgetfulness, suggesting cognitive factors.
• Interviews clarified that forgetfulness (items 1, 4, 8) was often linked to cognitive deficits or chaotic routines, validated indirectly by psychological scale correlations.
• Significance: This study validated forgetfulness through psychological and clinical correlations, highlighting cognitive barriers in psychiatric populations. While lacking objective measures like electronic monitoring, it provided robust subjective validation.
4. Hypertension in Seniors Study (2009)
• Source: New medication adherence scale versus pharmacy fill rates in seniors with hypertension, American Journal of Managed Care (2009)
• Methods:
• Pharmacy Refill Records: Compared MMAS-8 scores with pharmacy fill rates in hypertensive seniors.
• Clinical Outcomes: Blood pressure control was used as a proxy for adherence.
• Findings:
• MMAS-8 responses, including forgetfulness items (1, 4, 5, 8), showed moderate concordance with fill rates. Patients reporting forgetfulness had lower fill rates, supporting the validity of these items, though discrepancies suggested some intentional non-adherence.
• Better blood pressure control correlated with higher MMAS-8 scores (p < 0.05), indirectly validating reported adherence behaviors.
• Significance: This study used objective pharmacy data and clinical outcomes to confirm that forgetfulness is a measurable barrier, though it highlighted the need for additional methods to rule out intentional factors.
5. Technology-Based Adherence Review (2020)
• Source: Technologies for Medication Adherence Monitoring and Technology Assessment Criteria, PMC (2020)
• Methods:
• Electronic Monitoring Devices: Reviewed studies using Medication Event Monitoring Systems (MEMS) and video-based directly observed therapy (VDOT) alongside MMAS-8.
• Intervention Trials: Evaluated reminder systems (e.g., smart pill bottles, apps) to test forgetfulness as a barrier.
• Qualitative Studies: Analyzed patient experiences with adherence technologies.
• Findings:
• MEMS data showed that MMAS-8 forgetfulness items (1, 4, 8) overestimated adherence compared to actual bottle openings, with discrepancies in ~30% of cases. However, intervention trials with reminders reduced missed doses by 20% in patients reporting forgetfulness, validating these claims.
• Qualitative data confirmed that forgetfulness was often tied to complex regimens or travel (item 4), supporting the situational nature of unintentional non-adherence.
• Significance: This review demonstrated that electronic monitoring and interventions provide strong evidence for forgetfulness, with reminder trials offering practical validation by improving adherence.
Why These Studies Matter
These studies collectively validate the MMAS-8’s unintentional non-adherence questions by:
• Cross-Referencing Objective and Subjective Data: Pharmacy refill records (e.g., asthma, gout, hypertension studies) and electronic monitoring (2020 review) provide objective benchmarks, while interviews and patient-reported outcomes add context, confirming forgetfulness as a barrier.
• Testing Interventions: Reminder systems (2020 review) directly validate forgetfulness by showing improved adherence, as seen in trials where smart pill bottles addressed issues flagged by items 1 and 8.
• Exploring Cognitive Factors: The psychiatric study (2014) links forgetfulness to cognitive and psychological barriers, offering indirect validation through correlations with mental health measures.
• Highlighting Complexities: Discrepancies between MMAS-8 and objective measures (e.g., weak MPR correlation in gout study) reveal that forgetfulness may sometimes mask intentional non-adherence, prompting deeper investigation

​Academic literature has robustly validated the MMAS-8’s four unintentional non-adherence questions through integrated methods like pharmacy records, electronic monitoring, interviews, and intervention trials. Studies in asthma (2017), gout (2016), psychiatric care (2014), hypertension (2009), and technology reviews (2020) confirm that forgetfulness is a measurable barrier, though sometimes conflated with intentional non-adherence. These findings empower healthcare providers to tailor interventions—whether reminders, simplified regimens, or patient education—improving adherence and outcomes. As research continues to refine these methods, the MMAS-8 remains a vital tool for tackling one of healthcare’s biggest challenges.