Please remember, this column is designed to help the consumer seeking behavioral-health information, and not intended to be any form of psychotherapy or a replacement for professional, individualized services. I am not sure if you mean the social environment or the physical environment, but both certainly can contribute to the onset of depression.
Stress related to physical illness is connected to depression.
Also, drug and alcohol abuse is correlated with depressive symptoms. Family history seems to play a role in the onset of depression, with children of depressed parents having over two times the likelihood of developing depression. The physical environment can play role in depression, but since individuals vary in their response to environmental factors it is hard to sort out cause and effect. Scientists are still trying to sort these complex sorts of factors out. For further information visit the Depression Department .