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 theories suggest that anxiety stems from an unconscious conflict, an illness, fright, or emotionally laden event that happened to a person as a child. Life events and the way you have learned to respond to them may make you more likely to experience depression. Some medications for other illnesses can cause depression or mania, as can a medical illness.
Stress can bring on depression or mania in susceptible individuals.
Finally, in studying anxiety, depression and manic depression, scientists are learning the importance of genetics and 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. Also self-help support groups help people feel less isolated in that people can hear the words of others who have been through similar experiences.