In the mental health world, however, the term depression has a more specific meaning. Teens who meet the formal criteria for major depression feel down, empty, hopeless, or irritable for weeks on end. They may lose interest in most things they once enjoyed, and they may pull away from family and friends. Major depression can cause a wide range of other troublesome symptoms as well, such as changes in eating and sleeping habits, frequent tiredness, feelings of worthlessness, and, at times, thoughts of suicide.
