The cerebral course of essential hypertension is reviewed. By combined studies of a psychiatrist, neurologist, internist and psychologist, a psychiatric syndrome is defined, consisting of changes in the expression of hostility, willingness to yield to dependent needs and reduction in perfectionistic drives. There are also mild judgment and memory defects, insomnia, loss of energy and anxiety symptoms that are not explicable by changes in the cardiovascular status. The appearance of this syndrome signifies the onset of organic involvement of the brain. The duration of the disorder depends not so much upon the quantitative aspects of the cerebral damage as upon the integrative ability of the premorbid personality.