Stress Alters Kids' Brains, Study Suggests. Some stress is normal, but chronic strain may be linked to brain changes, scientists find. ... The brain differences also bore out in cognitive ability, with those children with highly stressful lives performing poorer than other kids on spatial memory tests.
Higher IQ protected against the PTSD response to traumatic events. ... Previous studies on the role of IQ in PTSD did not test the hypothesis that the influence of IQ varies by trauma severity, specifically that it has a stronger impact when trauma is less severe.
There are many studies that support the conclusion that experience changes the brain. See, for example, a working paper from Harvard University's Center on the Developing Child "Excessive Stress Disrupts the Architecture of the Developing Brain." ... Stress mobilizes hormones like cortisol and adrenaline in the child.