In the article "What Causes Depression?", Dr. Arthur Nezu discusses some of the possible reasons of people developing depression. There is no single cause to depression. Research has begun to find the possible reasons to why individuals develop depression. Some of these factors involve genetics, biology, environment and psychology. Dr. Nezu stated that "many theories talk about vulnerability to these factors stated previously however when individuals go through a stressful event, it makes them more susceptible to depression". Genetics is definitely apart of why individuals develop depression but the exact genes have yet to be recognized. We do know that depression runs in families and is more common when individuates have first-degree relatives with depression as well. One report from the American Psychiatric Association showed that When one identical twin has depression the likelihood of the other twin also developing depression is 70%. Also, depression may be linked to other diseases such as heart disease, cancer and neurological disorders. When it comes to depression I think more concern should be taken when the disease is mentioned, this disease just doesn't affect one individual it alters the lives of everyone around that individual as well.