Recent research in rats provides new information on the mechanisms by which stress causes symptoms of depression as well as how antidepressant medications act to overcome them (Son H et al. Proc Natl Acad Sci USA. 2012;109:11378-11383).
Previous studies have linked decreased plasticity (the ability of brain cells to reorganize in response to new events) in the brain's hippocampus to chronic depression. In this study, investigators from the United States and South Korea found that chronic unpredictable stress decreases hippocampal expression of a gene that regulates neuronal plasticity by producing a protein called neuritin and that antidepressant treatment reverses this effect.
Hampton T. Chronic Stress and Depression. JAMA. 2012;308(5):444. doi:10.1001/jama.2012.9458