The idea that psychological factors can influence blood pressure is at least 100 years old. Whether anxiety and depression contribute to the development of high blood pressure has been addressed in several studies although the results have been inconclusive and a recent Norwegian study found that anxiety and depression were actually linked to low blood pressure. The same team of researchers looked at data from 36,530 men and women between the ages of 20 and 78. The participants were asked about their levels of anxiety and depression and their blood pressure between 1984 and 1986 and were re-examined 11 years later. The researchers found that a high symptom level of anxiety and depression at the initial stage of the study predicted low blood pressure eleven years later and that changes in anxiety and depression between the two studies predicted changes in blood pressure.
Hildrum, Bjorn ... [et al] - Effect of anxiety and depression on blood pressure: 11-year longitudinal population study British Journal of Psychiatry August 2008, 193(2), 108-113