It's not entirely accurate to say that people aren't born with PDs, since they typically require a genetic predisposition to develop from a more proximal cause later.
I was diagnosed with Obsessive-Compulsive Personality Disorder when I was 17, and I'm almost 34 now. I was seeing a therapist for depression for two years before that.
For me, I had a genetic predisposition to psychological illness, and a family life that was well-meaning if under-ambitious, but the thing that caused the disorder to develop was school bullying. I was bullied from 3rd to 11th grade at least. I got beat up at least once a year, but most of the abuse was social and psychological. I was harassed, teased, prodded, pilloried, torn down, humiliated, and shamed, and I couldn't figure out what the cause was. They just hated me. And since they were kids, they set about destroying me for it. And since the adults didn't care, they became participants.
I was nice to everyone. I wanted everyone to be my friend. All I wanted was a friend group like everybody else had rather than the random kid I'd play with or the bully who managed to manipulate me into believing he was actually my friend. But they sent me to the counseling department when I shouted back. They sent me to the principal's office to cool down when I was angry that someone had stolen my notebook again. The adults saw this as my struggle, and only I was capable of fixing it. They were 100% wrong. There wasn't anything I could do. The adults were telling me not to fight back, not to talk back, to pretend it didn't matter, to shake it off, all this stuff, but they never once said a thing to my torturers. Oh sure, the kid who punched me in the face for asking for my jacket back got suspended for two weeks. Then he and his friends picked on me relentlessly for weeks about how much of a weakling and a whiner I was. Then he kicked me through a door the next year.
I was in art class in 3rd grade, and a kid in the back row had been chucking crayons at the back of my head as hard as he could. The teacher didn't notice the first time, or the second. I let it go again and was patient for the teacher to do what the adults said the teacher would do. Third crayon. Fourth. Fifth. Sixth. "Stop it! Teacher! He's throwing things at my head!" "Andrew, go to the hallway and get a drink. Other kid, cut that out." Later we go for a restroom break, and the teacher can't go in the boy's room. I wash my hands, and the next thing I know, the kid has picked me up, swung my head upside down, and then slammed me as hard as he could, head-first, onto the tile floor. I was dizzy and sick. I saw stars. My head ached the whole day. I screamed and pointed and told the teacher what happened.
He was back in class the next day.
The year afterward, after telling me some rude things about my mother and me having the gall to tell him to shut up, he jumped me on the playground and beat me in the back and in the back of my head.
He was back in class a week later, bragging to everyone about how much I'd cried, telling everyone I'd wet my pants. The teacher says, "Okay, settle down now, time for spelling."
