Probably both. That being said, life circumstances as a child still have way more to do with it than intelligence. There are a lot of relevant factors, and they all affect each other, so it's really better to assess cases individually.

That's actually not true. Higher intelligence is correlated with anxiety, depression, and substance abuse. That doesn't mean it's always the case, but the more intelligent one is the more likely they are to have those mental health problems.

That was the single passage that stuck with me the most. It's so beautiful and sad. I think about it on occasion.