Stress

Stress is mental or physical tension brought about by internal or external pressures. Researchers have found significant biochemical changes that take place in the body during stress. Exaggerated, prolonged, or genetic tendencies to stress cause destructive changes which lower the body's immune system response and can lead to a variety of diseases and disorders. These include depression, cardiovascular disease, stroke, and cancer.

People experience stress from many different sources. It can come from having to take a test or dealing with a difficult person; from traumatic experiences such as the death of a loved one, or a serious illness. Stress can be acute—as in the face of immediate danger when the "fight-or-flight" response is triggered; or chronic—such as when a person is involved in a long-term stressful situation.

People who experience severe traumas, as do soldiers during combat, may develop a condition called post-traumatic stress disorder (PTSD). During World War I this was called shell shock; during World War II it was called battle fatigue. Since 1980, PTSD has been listed as a diagnostic category by the American Psychiatric Association. Sufferers of PTSD experience depression, feelings of guilt for having survived, nightmares, and flashbacks to the traumatic events. They may be excessively sensitive to noise, become violent, and have difficulty holding a job.