Similarly, there is evidence that the prefrontal cortex - a key structure in emotional regulation as well as in decision-making and working memory - shrinks in major depression. On the other hand, rather than atrophying, the amygdala, the seat of emotional memories, becomes hyperactive both in post-traumatic stress disorder and depressive illness, and there is evidence from animal studies of a hypertrophy of nerve cells after repeated stress.
同样地，有证据显示，在主导型抑郁症中，前额叶皮层--情绪调节、做决定以及工作记忆的关键组织--也会萎缩。另一方面，在创伤后压力障碍症和抑郁症中，类扁桃体--感情记忆的所在--非但不萎缩，还会变得亢进。动物研究得到的证据还显示反复的压力之后神经细胞会变得过度肥大。