How to Assess Medication Adherence in Psychiatric Outpatients
How should clinicians assess medication adherence in adult psychiatric outpatients taking oral medications?
Medication nonadherence in psychiatric care drives relapse, rehospitalization, and worse outcomes, but the causes are often multifactorial. This guide applies to adult psychiatric outpatients on oral medication when a clinician needs a structured way to identify likely adherence problems and interpret the result in context.
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Confirm that the patient fits the assessment population
Use this approach for adult outpatients aged 18 years or older who have been taking oral psychiatric medication for at least 1 month. The study excluded patients with acute psychosis, cognitive impairment precluding informed consent, or inability to complete questionnaires, so interpretation is most applicable to patients who can reliably self-report.
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Measure adherence with the 10-item MARS
Administer the validated 10-item Medication Adherence Rating Scale as the adherence measure. Classify the patient as adherent if the MARS score is 6 or higher; in the study, scores of 6 to 10 were counted as adherence.
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Interpret the score alongside diagnosis-specific risk patterns
Recognize that adherence varied across diagnoses in this outpatient sample, with the lowest observed rate in psychosis at 30.8% and the highest in generalized anxiety disorder at 85.0%. Use that pattern to heighten concern about nonadherence in psychotic disorders, while remembering the article found that clinical variables overall were not statistically associated with adherence.
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Probe barriers beyond tablet appearance
Do not assume that dissatisfaction with tablet shape, size, or color explains nonadherence, because no significant associations were found between any preference or dislike and adherence. Focus the clinical discussion on psychosocial and illness-related barriers highlighted by the article, including poor insight, side effect fears, stigma, lack of social support, illness severity, and therapeutic alliance.
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Use self-report cautiously when concerns persist
Treat a MARS result as informative but not definitive, because the article notes that self-report may overestimate adherence through recall and social desirability bias. The cited validation literature showed only moderate concordance with objective measures, with kappa values of 0.4 to 0.6.
Clinical Considerations
- This approach is based on a cross-sectional single-center outpatient study and cannot establish causality.
- The study used self-reported MARS rather than objective adherence measures, so adherence may have been overestimated.
- The findings are most applicable to adult urban psychiatric outpatients taking oral medication for at least 1 month.
- The analysis did not adjust for confounders with multivariable models.
Bottom Line
Use MARS to structure adherence assessment, but investigate insight, psychosocial barriers, and therapeutic alliance rather than relying on tablet appearance to explain nonadherence.
