Sometimes differences in brain chemistry can affect mood and cause depression. Sometimes people become depressed for no clear reason . Depression is sometimes linked to prescription drugs or certain illnesses. Some medications used to treat arthritis, heart problems, high blood pressure, or cancer can cause depression as a side effect. These side effects may not happen right away.
Scientists also think some illnesses can cause depression.
These include Parkinson's disease, stroke, and hormonal disorders. Genetics , too, can play a role. Studies show that depression may run in families . Children of depressed parents may be at a higher risk. In some people, depression is inherent and occurs even when life is going well. .