Hypothetically speaking here Lets say someone was kept in a big enough room so that they won't go crazy from being in a small space, and pretty much everything you need to survive and be healthy, like a sterilized room so they cant get sick, properly fed, and they can't have a way to play with anything or kill themselves. Basically its a person in an empty box, and they are kept in it at birth. What would happen to them?
Crazy ass hallucinations probably, I've heard as little as 36 hours without human contact has an effect on your mental state. I've also done experiments with stimulation deprivation (also known as the Ganzfeld effect) to cause hallucinations and that can be done in as little as 30 minutes.
I think that the average person would go completely insane but wouldn't die from being bored. They'd pry end up smashing their head against the wall until they died. But, if they were raised there until birth I have no idea because that means that would be all they ever knew, but I don't think they would die from boredom..
They would suffer from major psychological issues. Mental ability and well being start to degrade after a few weeks of isolation. That is the reason some prisons will have a minimum amount of time they put prisoners into isolation. The first part is punishment, then they have to start attempting to repair mental damage before returning people to population. It's also the reason long term max prisoners often turn in to fucking animals, because they get treated like one.