Considerable attention has been paid to the examination of behavioral or psychological factors related to medical disease outcomes. Borrowing the term ‘stress’ from the field of physics, psychological researchers have distinguished environmental stimuli, known as stressors, from stress responses. Stress responses have included the affective, cognitive, behavioral, and physiological alterations that occur immediately in response to the eliciting stimuli, as well as the more chronic stress responses that consist of psychological disorders and physical diseases.

Researchers examining the influence of stress upon health can be categorized into three groups: those that have focused on stress as a response, those that have focused on stress as a stimulus, and those that have adopted transactional or interaction models incorporating both stimulus and response components. 

Among investigators focusing upon stress as a response, greater attention has been paid to the physiological stress response of the organism and how it translates into physical manifestations of disease. Researchers who have focused upon stress as a stimulus have typically investigated different categories of stimuli (psychological stressors, physical stressors), determining the relation between specific stressors and disease outcomes.

Finally, those investigators employing transactional perspectives have focused upon the bidirectional influences between environmental stressors and resulting stress response patterns.

Stress researchers have long acknowledged that two organisms exposed to the same environmental stressor typically exhibit differential stress responses. These observations have led to a greater examination of individual difference variables that may influence the relation between the stress stimulus and the stress response.

Several individual difference variables have been identified and examined, including demographic and historical developmental variables, modifiable psychophysiological variables, and modifiable social variables. In brief, many individual difference variables must be considered when attempting to predict the magnitude of stress response to a given stimulus.

Common themes among existing theoretical perspectives permit the development of a comprehensive model of stress. Although not as detailed as some previous models, this broad model contains elements of the stressor??“stress response relation that have uniform agreement among current stress researchers. In particular, a diathesis??“stress approach is taken in the conceptual model proposed, in that individual differences play a central role through an accumulated parameter called vulnerability to stress.

Both vulnerability to stress and environmental stressors are proposed to interact in influencing the magnitude and patterning of the acute stress response. To refer again to the case of Franklin, very little attention was paid to the current life stressors he was experiencing at the time of diagnosis.

He had just experienced a very traumatic rescue attempt, and his father had experienced a heart attack a few years previously. Although both of these environmental stressors could have influenced measures of blood pressure, they were not given much attention during his medical evaluation. As such, it was unclear whether his increase in blood pressure represented a chronic condition that warranted treatment or whether the increased blood pressure was part of an acute stress response that might dissipate with time.

In cases such as Franklin’s, it is often difficult to disentangle the various genetic and environmental factors contributing to elevated arterial pressures.