Stress causes neurogenesis to slow down and even stop, causing the hippocampus to shrink in size and reduce its capabilities, thus propagating the spiral that becomes depression.
Stress isn’t the only thing that is linked with a smaller hippocampus, there is also a link with high levels of consumption of alcohol, sugar and saturated fats. There are positives as well, such as physical exercise, mental stimulation, eating grapes and blueberries, getting enough sleep, sexual activity (in moderation) and more besides. Anti-depressants also boost neurogenesis, but there are natural anti-depressants in the forms listed above, without the side effects. Anybody with major depressive disorder would benefit from combining medication with a healthy lifestyle and stress management. A healthy body and a healthy mind go together, so the best bet for anybody with depression is to maintain good habits and rest assured, that bad days will be more bearable and good days will be better if you look after your body and your mind.