What is the best way to achieve concordance? The authors summarise the evidence and indicate the way ahead for doctors to involve patients in making decisions about treatment

Much prescribed medicine is not taken, and we know that few patients adhere to “prescription” guidance.1 It is also clear that patients' beliefs and attitudes influence how they take drugs.2 This is particularly true for preventive medicine (thus largely for conditions without symptoms) and for drugs that have side effects or other drawbacks. As interest in the concept of patient autonomy increases, we are becoming more aware, and more respectful, of intentional dissent—where better informed patients decline certain drugs.3 Concordance describes the process whereby the patient and doctor reach an agreement on how a drug will be used, if at all. In this process doctors identify and understand patients' views and explain the importance of treatment, while patients gain an understanding of the consequences of keeping (or not keeping) to treatment.