At highest risk are individuals who have already experienced an espisode of major depression, have close relatives with severe depression, or who abuse alcohol or drugs. Depression may strike any age group from young children to seniors with an average onset in the mid-twenties.
Woman are two to three times more likely to develop depression than men.
Some individuals may be able to point at various life events and be certain they are the reasons for their depression. Depression is an illness characterized by neurochemical abnormalities that can cause significant disability. The cause may be one or a combination of biological, genetic, chemical, psychological, social, developmental and environmental factors. Heredity, brain chemistery, hormonal systems and sleep-wake controls are included in biological factors. Many depressed individuals do not realize they are seriously ill.