Chronic stress can cause hippocampal shrinkage and worsen Alzheimer's predisposition, schizophrenia, and addiction relapse.

“And indeed they are frightening. You see the nice really plump brain on the left. It says healthy or control. And then you see the brain that says stressed above it on the right and it's like withered, where we see that the hippocampus and area involved in memory is smaller. People that are stressed. We see that the Alzheimer's brain is made worse by stress. That people who have a predisposition to schizophrenia, when they get stressed, higher incidence of schizophrenia episodes. You hear that addicts will relapse when they're stressed.”