They found that the more symptoms a kid had, the higher his cortisol levels were and the smaller the volume of his hippocampus. After the first measurement of the hippocampus, they measured the same kids again twelve to eighteen months later and found their hippocampi were even smaller. Despite the fact that these kids were no longer experiencing trauma, the parts of their brains responsible for learning and memory were still shrinking, showing us that the effects of earlier stress were still acting on the neurological system.
