The extent to which patients take prescribed medications ‘as directed’and why they do not have been important issues in health research for many decades [1] and subject to recent review [2–6]. These issues are important in rheumatic diseases, given the primary reliance upon medication to control symptoms and improve patients’ functional ability and longevity [7]. Not taking required medications can therefore have both a personal health impact and health-economics consequences [3]. In recent years patients have shown increased interest in their health-care; this is partially due to a boom in access to information technology coupled with increased health coverage in traditional media sources [8]. A fresh approach to medication prescribing is required, one that evolves away from the paternalistic approach of patient compliance or adherence towards the more recently introduced philosophy of patient–professional concordance. Previous research has lacked consistent definition and measurement of medication-taking and, particularly in rheumatology, has rarely investigated biopsychosocial predictors in a longitudinal or interventional fashion. In this editorial we reiterate the definitions of patient ‘compliance’and ‘adherence’and comment on the implications of using these terms. We review some of the relevant research findings on patient compliance/adherence in rheumatology and finish by outlining the more recent philosophical and clinical move towards patient–professional concordance along with some of the practical implications for its impending application in routine clinical practice. We highlight potential predictors of medication taking that should be integrated in future research. We also examine how medication taking and its potential predictors should be measured in research by detailing key methods and identifying areas in which they can be applied. Definitions of key concepts and our recommended measures of these are summarized in Table 1. The conceptualization and operationalization of the ‘correct’taking of prescription medications often reflects the dominant paternalistic approach to health-care. As Charavel et al.[9] put it,‘the physician–patient relationship has always implied that the physician alone makes the treatment decision, while the passive and dependent patient is obliged to comply with the physician’s prescription.’(p. 93, emphasis added.) The verb ‘comply’implies enforcement through its association with ‘bending the will of another’([10], etymology section). This has led to increased use of the verb ‘adhere’, which literally means ‘to stick to’([11], etymology section), to describe medication-taking.‘Adherence’is described as ‘persistence in a practice or tenet; steady observance or maintenance.’([12], section 3). This definition captures the routine that people with chronic rheumatic disease ideally engage in when taking prescription medication.

The classic estimate of adherence is that only around 50% of patients adhere to prescription medications [1]. Ten days after a new prescription has been filled, 30% of patients with chronic diseases have missed at least one dose of the medication not on medical advice, half of them unintentionally, the others intentionally [13]. Reasons for missing a dose include side-effects, concerns