What are the causes and symptoms of depressive disorders?
The causes behind depression are complex and not yet fully understood. While an imbalance of certain neurotransmitters —the chemicals in the brain that transmit messages between nerve cells — is believed to be key to depression, external factors such as upbringing (more so in dysthymia than major depression) may be as important. For example, it is speculated that, if an individual is abused and neglected throughout childhood and adolescence, a pattern of low self-esteem and negative thinking may emerge. From that, a lifelong pattern of depression may follow. A 2003 study reported that two-thirds of patients with major depression say they also suffer from chronic pain. A 2004 study linked severe obesity with major depression. Another study showed a strong relationship between smoking and depression among teens. Heredity seems to play a role in who develops depressive disorders. Individuals with major depression in their immediate family are up to three times more likely to have the diso
