Ideas about persons with mental illness as violent often result from 
larger cultural and political anxieties.

People believe that psychiatric diagnosis is a predictive tool. It is 
not. Psychiatrists see many patients who fit the criteria for violent 
behavior: They're angry, threatening and sometimes paranoid. However, 
only a very small percentage of the patients ... are actually violent.*

A theory is likely to be accepted if it tells a story that benefits a 
powerful constituency.

"Do you know what undeniably influences people in a violent 
direction? Hanging out with other potentially violent men and drinking."**

* 
<https://news.vanderbilt.edu/vanderbiltmagazine/qa-with-dr-jonathan-metzl/>https://news.vanderbilt.edu/vanderbiltmagazine/qa-with-dr-jonathan-metzl/

** Stephens-Davidowitz, Everybody Lies, Harper-Collins, 2017, p 196

www.peoplewho.org