ABSTRACT
There is abundant evidence that the arterial blood pressure (BP) is influenced by the individual's interaction with the environment. A most dramatic example of this is represented by those studies where continuous intraarterial recordings of BP were made over periods of up to 24 hours in normotensive individuals where the range of the systolic blood pressure (SBP) was found to vary up to 100 mm Hg from sleep to emotional excitement (Bevan, Honour, & Stott, 1969). Of more direct relevance to the role of behavioral factors in the etiology of essential hypertension are reports of the development of elevated BP's in animals exposed to environmental events such as shock avoidance (Forsyth, 1969; Morse, Herd, Kelleher, & Grose, 1971), social isolation followed by crowding (Henry, Stephens, & Santisteban, 1975) and experimental conflict (Lawler, Barker, Hubbard, & Allen, 1980). In humans, cultural factors such as social structure (Henry & Cassel, 1969) or socioeconomic status (Tyroler, 1977) are reported to relate to an elevated BP. While these various lines of evidence implicate behavioral
events in the etiological process in the sense that they are necessary first steps, they are not all that informative in certain other respects. For example, they do not indicate in any definitive manner why only a certain percentage of the population ever becomes hypertensive, thus preventing us from identifying such individuals with any confidence until the BP is elevated and sustained. In addition, they fail to delineate the hemodynamic basis (mechanisms) responsible for the development of hypertension and the manner they interact with behavioral events. It must be emphasized that an elevation of the BP is only a symptom indicating a derangement of one or more of the mechanisms which control it. It does not tell us which mechanisms are involved, how the derangement came about, or how it should be treated and prevented. An analogous situation is seen with another common sympton: the presence of a fever does not reveal what the infecting organism is, the site of the infection, the events and circumstances that led up to it, nor the appropriate treatment and preventative measures. The analogy can be extended to those treatments of an elevated BP which focus just on the BP, as is common with any behavioral intervention technique. This is no differ· ent in principle from treating a fever with aspirin. The necessity to delineate the mechanisms and the behavioral input is also indicated by the possibility that an elevated BP may reflect different etiological processes among individuals and that behavioral influences may be of greater significance with some etiologies than with others. Insight into the etiological process thus is fundamental for any effort in prevention or treatment.
