Neurobiologically http://www.ncbi.nlm.nih.gov/pmc/articles/PMC60045/ Depression, antidepressants, and the shrinking hippocampus Neurobiologically encouraging neurogenesis Neurobiologically - ncbi.nlm.nih.gov up to 20 percent http://www.ncbi.nlm.nih.gov/pmc/articles/PMC60045/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC60045/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC60045/ - ncbi.nlm.nih.gov shrinking of the hippocampus up to 20 percent Neurobiologically Sapolsky â Stress and Depression