Developing evidence for how to tailor medical interventions for the individual patient

We aim to answer the question: How can we develop an evidence base that will assist tailoring health interventions to individual patients? Using social theory and interview data from people living with chronic illness, we developed a new approach to analysis. Individuals were considered as emergent complex systems, adjusting and adapting within their environment and sometimes transforming. The notion of illness trajectory brought our attention to data in the interviews about the "emergent present," the current period of time when all domains of life, from across time, have expression. We summarized patterns of adjustment and adaptation within the emergent present for people living with chronic back pain, depression, and diabetes. We considered the potential of this analysis approach to inform medical decision making. Our analysis approach is the first step in developing a categorization of individuals that might be useful in tailoring health care interventions to the individual.