The unifying concept of illness behavior.

The concept of illness behavior was introduced to indicate the ways in which given symptoms may be perceived, evaluated and acted upon at an individual level. Illness behavior may vary greatly according to illness-related, patient-related and doctor-related variables and their complex interactions. In the past decades, important lines of research have been concerned with illness perception, frequent attendance at medical facilities, health care-seeking behavior, treatment-seeking behavior, delay in seeking treatment, and treatment adherence. They have, however, mostly investigated single aspects separately. In this concise review, we suggest that the concept of illness behavior may provide a unifying framework and useful insights to observations and findings that would otherwise remain scattered and unrelated in the medical literature. The wide range of expressions of illness behavior is likely to affect the presentation of any disease and its identification, course and treatment. Assessing illness behavior and devising appropriate responses by health care providers may contribute to the improvement of final outcomes.