A growing amount of scientists support the view that people with depression have an imbalance of the brain's neurotransmitters, the chemicals that allow nerve cells in the brain to communicate with each other. They believe that an imbalance in serotonin, one of these neurotransmitters, may be an important factor in the development and severity of depression. Abnormal serotonin functioning is theorized to cause psychological disorders such as depression, anxiety, irritability, abnormal appetite, and sleep disturbance. …
