Given that the majority of women in my extended family seem to suffer from some kind of depressive disorder to a greater or lesser extent, I've always been interested in the research going on in that area. It has always seemed a little astonishing that although there have been drugs to treat depression for a relatively long time, 20 years, there isn't a good understanding of how they work, why they work, what they are really doing. Yes Prozac is a selective serotonin reuptake inhibitor, SSRI, which means that it increases the amount of serotonin in your brain available to post-synaptic cells by reducing its absorption by pre-synaptic cells. And that seems to be a good thing, but exactly why it is a good thing still isn't firmly established. SSRI's change your brain chemistry soup in a matter of hours, but it takes weeks for this to translate into an easing of depression.

Anyway, I just read an article that talks about how the theory that SSRI's work by increasing neurogenesis has made a little more progress. I've heard the theory before, and it is interesting to see that the research behind it is progressing bit by bit. Also some counter arguements about the length of time that it takes neurons to mature in humans vs mice. Brains are neat. "New life inside the depressed brain: Neuron growth may be key to mood disorder treatments, studies find"