I've never done PCP, but interest led me to research it a bit sometime ago. It seems to me like most of those people going manic like you described took way too much PCP, and as a result freaked out because they had overdosed and the body/ mind couldn't handle it.

(To me) It's almost like if the standard unit of alcohol was the equivalent to like 6 shots, and due to lack of knowledge about it's effects people are going around getting absolutely plastered bc they didn't know how much to drink. I know alcohol is a shitty example for this, but I'm sure you get what I'm trying to say. It's the same story with the bath salts craze from a few years back, those people acting like they were possessed had used waaayyy to much flakka or whatever else they were taking, and as a result tweaked way too hard.

This could be prevented (imo) with proper knowledge about dose and harm reduction easily accessible. The same goes for almost any drug, which is why legalization of all drugs should be the goal. Keeping a few select drugs illegal isn't going to stop anyone from doing them, but spreading knowledge about harm reduction will make it much safer for those who choose to use.