50% of Americans are mentally ill according to the official mental health site. 25% have chronic life long illness and 25% have episodic effects.
Coming from the outside, I think there are several factors that have brought this about.
1. Americans are socialized to believe the biggest load of bullshit out. When reality confronts this, it becomes very stressful.
2. The type and amount of food that Americans eat is a nightmare. It destroys the body and the brain.
3. The stress of working and the dog-eat-dog society Americans live in would destroy any human being. Human beings were not meant to live that way.