I saw porn as a kid initially because some blew into my Grandparents' back garden from a neighbour who'd had his stash ripped up.. Probably some domestic there, but I can remember wondering why the women were wearing pretend beards in strange places. I thought it was funny and an oddity.. Couldn't have been more than 6 at the time..
Then a few years later (still sub 10), one of my friends uncovered his dad's stash.. There was the thrill of doing something I knew I wasn't meant to be doing, but nothing out of the ordinary. No ill effects, apart from the fallout from having my folks hit the roof when they found out about it..
A few years later, I watched a horror movie (that would be considered tame by today's standards) and I didn't sleep properly for weeks, and I remember being so nervous and anxious for ages.. Hey, I got over that too.. But from my perspective and recall, being exposed to horror and violence is far more damaging to a young psyche than porn.. But being young, you get over it.
Now for real problems, you just have to step over into a third world country where death is common and visible, people you know are abducted and killed. Disease is rife and a killer. And yet some of them are far more well adjusted than a lot of the people I've seen raised in 'safe' environments...