I worked for 28 years....
I suppose THC is like alcohol in that you build up a tolerance. When it became legal in Colorado lots of new users tried it and got some huge doses with edibles. I think these are the ones with the biggest problems. A lot of people get in trouble driving high and get involved in a wreck. I suppose the ones that are in denial whether pot or alcohol are the most dangerous ones.
Some people are more prone to psychosis if there drink or do drugs.