> environmental factors 

Yeah I did make mention of these enviromental factors by all means. But then the fact that a lot of variables are responsible for how personalities are formed is why it's totally difficult to place a finger on it, but I sure did touch the basics. Thanks for culling that definition off the internet. 
Truth is, it gets to a stage where personality becomes biological, it gets really broad and extends to the medical field and that's where you'll get this personality disorder of thing. Its more of a mental thing induced by the effect of unbearable experiences, in my own assertions.