Background
Clinical Depression
All of us feel depressed sometimes. We have good days and bad days, and sometimes the bad days stretch into bad weeks. But these normal mood swings are only a pale imitation of clinical depression, a serious disorder that may dominate the life of the depressed person and his or her family and friends. Society also bears the cost of depression in terms of lower job productivity and higher health-care expenditures. Indeed, depression is now the most common mental health complaint; it is ten times more common now than it was fifty years ago. Some researchers claim that depression is responsible for more human suffering than any other single disease or disorder.
Symptoms of Depression
Most depressed people show several related symptoms, as shown here. These symptoms may be normal reactions to unpleasant life events; they are considered major depression only when they last more than two weeks and are serious enough to interfere with daily life.
Causes of Depression
Why do people become depressed? Theories abound. Some stress biological factors, including a possible genetic predisposition, drawing support from the fact that depression tends to run in families. One particularly promising line of research focuses on two neurotransmitters, norepinephrine and serotonin; the levels of these substances are generally lower in the brains of depressed persons.Other theories emphasize the role of stressful events in childhood or in the recent past, especially the loss of something important. Sigmund Freud, who originated the psychoanalytic perspective, thought that depression was a reaction to a current loss that symbolized the loss of a parent or a parent's love. Infancy researchers Rene Spitz and John Bowlby noted that children separated from their mothers sometimes developed depressive symptoms very similar to those of adults with major depression.
Learning theorists suggested that repeated negative experiences may condition a person to expect bad events in the future. Cognitive-learning theorists extend learning theory to include the person's interpretation of the situation.
Most researchers now realize that depression has more than one cause, and that most cases of depression probably result from the interaction between a genetic predisposition and a particular set of environmental experiences.