http://www.huffingtonpost.com/samuel-j-mann-md/stress-and-hypertension_b_2517600.html
.....Over decades, thousands of studies funded by hundreds of millions of National Institutes of Health dollars have been performed. It is long past time to ask: What has this enormous body of research taught us regarding the understanding or treatment of hypertension? Should further money be poured into mind/body research in hypertension? In this two-part blog, I will address these questions, based on what research tells us, and based on my own research and clinical experience.
It is clear that in most cases, genetic factors and health habits (diet, weight, salt intake, lack of exercise) are the major contributors to hypertension. In my professional estimation, about 40 percent of hypertension is attributable to genetic factors, and another 40-50 percent to health habits. Healthy diet and exercise have been consistently shown to lower blood pressure. In some they normalize blood pressure, but in many they don't, either because of genetic factors that don't respond to these measures, or because of inadequate adherence to healthy habits. Here, medications will usually do the job, and, in fact, 50 of the 75 million Americans with hypertension are taking medication.
What, then, is the role of psychological factors? Psychological studies in hypertension focus on identifying psychological causes, but not on the proportion of hypertension that is attributable to psychological factors. My research and experience suggest that psychological factors do not play a major role in most cases, but are very relevant in about 10-15 percent, and that research attention should be focused on that 10-15 percent and not on everyone with hypertension. ........