A great many neuroscientists are interested in clinical depression and antidepressants. We're still a long way from understanding depression on a biological level - and if anyone tries to tell you otherwise, they're probably trying to sell you something. I've previously discussed the controversies surrounding the neurotransmitter serotonin - according to popular belief, the brain's "happy chemical". My conclusion was that although clinical depression is not caused by "low serotonin" alone, serotonin does play an important role in mood at least in some people.
A paper published recently in Molecular Psychiatry makes a number ofimportant contributions to the literature on depression and antidepressants; I haven't seen it discussed elsewhere, so here is make take on it. The paper is by a Portuguese research group, Bessa et. al., and it's titled The mood-improving actions of antidepressants do not depend on neurogenesis but are associated with neuronal remodeling. The findings are right there in the title, but a little history is required in order to appreciate their significance.