That’s an oversimplification of what personality disorders entail, and respectfully, your anecdotal experience cannot account for all the intricacies of different personality disorders and how they manifest in each individual. Even specialist have difficulty diagnosing them and some find the diagnosis controversial because there’s a lot of confounding variables and people are just complicated.
I will gladly shut up if you have sources, but I generally feel like most of us are not qualified to make such confident assertions about what causes people to kill. If it were that simple, it wouldn’t keep happening. And your claim that the vast majority of people who kill have a personality disorder or psychosis is
simply not true.
Of all homicides that had psychiatric reports at the time of conviction (n=1168):
11% had a personality disorder
6% had psychosis at the time of the offence