Patient compliance behavior: the effects of time on patients' values of treatment regimens.

Present medical models of treatment compliance have not addressed the role that time plays in the perception of a treatment regimen's costs and benefits. This paper re-evaluates the role of time in understanding compliance behavior. Models from the economic and psychological literature are used to demonstrate that the 'discounting effect' associated with future events, and the 'sunk cost effect' associated with past events may have a direct and predictable impact on the patient's values in health care choices. This article suggests that when the effects of time are incorporated into expectancy models of compliance behavior (such as the Health Belief Model) the resulting predictions are supported by numerous findings in the compliance literature, many of which were previously unaccountable by these expectancy models. From this finding an explanation is derived for the variable results of educational and attitudinal change programs upon compliance behavior, the success of patient contracts, the sudden occurrence of preference reversals in health care choices, and the 'confusing' effect of treatment cost on treatment adherence. This paper also introduces to the compliance literature the concept of a treatment's 'time adjusted rate of return', and speculates upon how this concept may be used to understand the relationship between a treatment's 'desirability' or its ability to motivate a person to start the treatment, and its 'resistance' or its capacity to help a person to finish the treatment once it has begun. It proposes that changes in the temporal distribution of a treatment's benefits and costs can improve the treatment's desirability and resistance, and that a treatment's time adjusted rate of return can be used to allocate more efficiently the effort that providers spend monitoring patient compliance.