Physically, being under a large amount of stress can be detrimental to the body's overall health, like high blood pressure, which can cause heart attacks, which in some cases lead to death. And insomnia can also be a cause from too much stress. Socially, it can cause you to be antisocial and to avoid social situations, it also can cause panic attacks and breakdowns. Emotionally it can cause depression, and again panic attacks, and an leave you angry/depressed.
