Theories about causes There is no single cause of anxiety or depression. Rather, physical and environmental triggers may combine to give rise to anxiety, depression, or manic depression in certain people. Some scientists believe that anxiety is a learned response, that people are taught to fear situations or objects. Some psychoanalytic theory suggests that anxiety stems from an unconscious conflict, an illness, fright, or emotionally laden event that happened to the victim as a child. Life events and the way you have learned to respond to them may make you more susceptible to depression.
Some medications can cause depression or mania, as can a medical illness.
Stress, like the loss of a loved one, a divorce or even a promotion at work, can all bring on depression or mania in susceptible individuals. Finally, in the cases of each of anxiety, depression and manic depression, scientists are learning the importance of brain biochemistry. Biochemical imbalances seem more and more to be a significant part of the problem. Treatments Anxiety, depression and manic depression are illnesses that can be treated very successfully with a combination of psychotherapy and medication. In cases of depression where other treatments have failed or are not possible, electroconvulsive therapy has been used with success.