The notion of medicines concordance, in which patients participate in decisions about medicines prescribed for them , emerged a decade ago as a potential way of increasing adherence with medication regimens. By adherence, we mean the extent to which a person's behaviour in terms of taking medication coincides with medical advice . Since its creation the concept of medicines concordance has been accepted in clinical practice without a theoretical framework for understanding whether, when and how medicines concordance is to be employed in clinical practice. We believe that recent calls ‘to abandon the term “patient concordance” altogether’ are emblematic of a need for greater theoretical understanding of medicines concordance. Only recently, there seems to have been some recognition of this need for greater knowledge about medicines concordance, with a critical appraisal of the evidence on shared decision making being conducted in the United Kingdom . We attempt to remedy current theoretical deficiencies by suggesting a simple framework for understanding medicines concordance and its application in clinical practice.
Medicines concordance was originally defined as ‘an agreement reached after negotiation between a patient and a health care professional that respects the beliefs and wishes of the patient in determining whether, when and how medicines are to be taken’. However, when attempting to put into practice medicines concordance, medical practitioners are likely to find themselves asking questions such as, ‘Shall I employ medicines concordance with all my patients?’‘ What types of patients would benefit the most from this approach?’ and ‘Why?’ We believe that the well-established theory of psychological reactance  offers an explanatory framework useful in answering some of these fundamental questions.
Brehm's theory of psychological reactance proposes that when we perceive that our freedom to select when and how to conduct our behaviour is being restricted by the actions of others, we tend to respond in a way that re-asserts our freedom to choose. Often we choose to do the opposite of what we have been recommended to do, even if we agree, in essence, with the value of the recommendation. A motivational state compels us to re-establish our freedom. This phenomenon is called psychological reactance. In his original formulation of the theory Brehm also posited that maximizing the individual's perception of free choice can restore a sense of autonomy and self-determination, thus mitigating feelings of reactance .
When applied to the area of adherence to medication regimens, the theory of psychological reactance makes two interesting predictions: (i) through limiting or threatening freedoms, recommendations to follow a medication regimen have the potential to elicit reactance and, as a result, lead individuals to ignore the recommended treatment; (ii) shared decision making between the clinician and the patient has the potential to enhance perceptions of free choice mitigating feelings of reactance.
In medicines concordance, patients participate in decisions about medicines prescribed for them, thus enhancing their perception of free choice, which potentially mitigates resistance to adherence induced by psychological reactance. Medicines concordance and psychological reactance seem to be two complementary concepts that are intrinsically related to adherence to medication regimens.
It is also noted that research has found psychological reactance to be one of the factors determining non-adherence to medication regimens . Individual variability in adherence to medication regimen has also been found to be related to individual variability in reactance as a personality trait . Additionally, research in the area of promotional health messages has found that enhancing perception of free choice, as suggested by the theory, minimizes the generation of psychological reactance .
Particular noteworthy is the fact that research indicates that reactance is a personality trait with levels of reactance varying from individual to individual along a continuum from very low to very high . This means that recommendations to follow identical medication regimens may lead to considerably different responses in different patients. Therefore, universal application of medicines concordance in clinical practice may not be appropriate, as not every patient is highly reactant.
It is reasonable to believe that non-reactant patients are likely to respond well to simple straightforward instructions from a medical practitioner. Such an explicit and directive communication style may also have a place in medication counselling as it conveys to the patient clear messages on what to do, leaving little room for ambiguity. Indeed, research on behaviour change in other domains of medical practice, such as problem drinking and smoking, suggests that straightforward advice from a medical practitioner can be effective in influencing behaviour . It is also important to note that not every patient agrees with the concept of shared decision making in clinical care. In a study of 344 patients living with rheumatoid arthritis, 50% reported the view that patients should go along with doctor's decisions even if they did not agree with such decisions ( cited in ).
It seems to us that practitioners would benefit from practical communication tools that would enable them to assess individual reactance levels during the consultation process allowing medication counselling to be tailored accordingly. That is, employing medicines concordance in circumstances when the practitioner detects reactance in the interaction with the patient and providing clear straightforward advice to patients who they feel are conducive to it. By maintaining congruence with patients’ reactance levels clinicians can potentially exert more influence on patients’ behaviour increasing the likelihood of adherence to treatment regimens.
Finally, we also believe that the theoretical clarity provided by the concept of psychological reactance has the potential to assist in research design and interpretation of results in the area of medicines concordance. In addition, a coherent theoretical framework may also facilitate the translation of medicines concordance research findings to useful applications in routine clinical practice.