Aptitude x treatment interactions in family medicine research.

A model for research, aptitude x treatment interactions (ATI), is presented. This model has some specific utility for family medicine research. ATI can test the interaction between individual differences (aptitudes) and experimental interventions (treatments). Thus, in an applied setting one might choose an intervention based on its suitability for a particular type of individual (as measured by some form of individual difference measure). Several studies confirm the usefulness of the approach, and examples are presented and discussed. Approaches to the study of ATI for the family medicine researcher are described with special attention to clinic based and patient education studies.