| MECHANISM OF ACTION |
But what upsets neurotransmitter balance in the first place? One theory is that depression shrinks particular regions of the brain. For instance, the hippocampus is smaller in patients who suffer from recurrent major depression than in comparison subjects. The hippocampus plays a role in learning and memory and is part of the limbic system, which is involved in emotion and motivation. Furthermore, the hippocampus tends to be smallest in those patients who go without treatment for their depression for the longest period of time. "The key implication of this study," writes Sheline's team, "is that antidepressants may protect against hippocampal volume loss associated with cumulative episodes of depression."
|