The Brain: Understanding Neurobiology
Sponsoring Institutes
skip navigation Main Getting Started Teacher's Guide Student Activities About NIH and NIDA
glossary | map | contact 
National Institutes of Health website National Institute on Drug Abuse website


National Institutes of Health
National Institute of Neurological Disorders and Stroke website

The Brain: Understanding Neurobiology

Main    Getting Started    Teacher's Guide    Student Activities    About NIH and NINDS

Glossary    Map    Contact

Lesson 5—Drug Addiction Is a Disease, So What Do We Do about It? student in a classroom

Teacher's Guide

dealing with a chronic diseasevideo interviewsadditional information

start of page content

start of page contentHypertension

The following is drawn from materials from the American Heart Association ( and the National Heart, Lung, and Blood Institute (

What is hypertension?
Hypertension, or high blood pressure, is defined in an adult as a blood pressure greater than, or equal to, 140 mm Hg systolic pressure or greater than or equal to 90 mm Hg diastolic pressure. Hypertension does not refer to being tense, nervous, or hyperactive. Optimal blood pressure for an adult is 120 mm Hg systolic and 80 mm Hg diastolic. Blood pressures are normally written as systolic/diastolic, such as 120/80.

In most cases, the cause of high blood pressure is unknown. This type of high blood pressure is called essential hypertension.

In the remaining cases (5%–10% of cases), high blood pressure, called secondary hypertension, is a result of another health problem such as a kidney abnormality, tumor of the adrenal gland, or congenital defect of the aorta. Blood pressure usually returns to normal when the underlying cause is corrected.

Symptoms and diagnosis:
Diagnosis of high blood pressure is based on the average of two or more readings taken at each of two or more visits after an initial screening.

Hypertension usually has no symptoms. Many people have high blood pressure and don’t know it. If hypertension is severe, symptoms may include:

The prescribed treatment depends on the severity of hypertension, but may involve the following components:

Long-term consequences of uncontrolled hypertension:
High blood pressure directly increases the risk of coronary heart disease (which leads to heart attack) and stroke, especially along with other risk factors. Uncontrolled hypertension can also lead to renal failure.

Long-term outlook for hypertension if treated and controlled:
Hypertension is controllable with treatment, which may require periodic adjustment.

See also: Heroin Addiction | Diabetes Type I