Severe stress in middle age can lead to Alzheimer's by damaging the brain, experts warn. 1  Canadian scientists believe neurons involved in chronic anxiety and fear 'extensively overlap' in areas also associated with Alzheimer's disease.  Stress in middle age could cause dementia by damaging the brain, new research suggests. Neurons involved in chronic anxiety and fear 'extensively overlap' in areas also associated with Alzheimer's disease, say scientists. Mid-life stress has been previously linked to a higher risk of Alzheimer's disease.