Yahoo! News - Antidepressants Grow New Brain Cells - U.S. Study: "depression can shrink the hippocampus, a brain region crucial to learning and memory but only recently found to be involved in depression. Major stress and trauma -- both depression triggers -- can also cause the shrinkage.
'We have known that antidepressants influence the birth of neurons in the hippocampus."

To make sure that the new brain cells in the hippocampus was the source of the lifted depression, Hen and colleagues at Yale University and in France worked with genetically engineered mice, using X-rays to kill newly growing cells in the hippocampus.


These mice did not respond as they normally would to antidepressants. Mice which were given fluoxetine, an antidepressant sold under the brand-name Prozac by Eli Lilly and Co., and were then given X-rays did not resume grooming as would be expected.


Mice who received no X-rays and were killed after being dosed for 11 or 28 days with fluoxetine showed significant growth of new brain cells.

A drug in a different class, the tricyclic imipramine, also stimulated the growth of neurons

Experts say that 16 percent of Americans -- more than 30 million people -- will suffer major depression at some point in their lives.


The NIMH says major depression is now the No. 1 leading cause of disability around the world.