More recent genetic research offers hope that scientists may soon be able to identify a genetic marker that indicates a susceptibility to manic-depressive disorder within some people. Chemical imbalances . Additional research data suggests that people suffering from depression have imbalances of natural substances within the brain that allow brain cells to communicate with one another. Other research shows alterations in body chemicals and hormones to be present in depressed people. But researchers are uncertain whether these imbalances are causes of depression, or result from it.
Life stresses .
Any kind of life change, good or bad, can sometimes trigger depression. A job promotion can prompt a bout of depression as easily as a job loss. The birth of a child is frequently followed by depression, as is the loss of a loved one. A serious illness . Depression may be linked to certain medications, such as pain relievers for arthritis, cholesterol-lowering drugs, and medications for high blood pressure and heart problems.