Hello, thanks a lot for your question!
INTERNAL THOUGHTS is pretty simple — it’s whatever you think your character would be thinking in the moment. There’s no limit. It could be things like “I need to get out of here,” “I think someone is hiding something from me,” “That sound in the dark isn’t normal,” or “I feel safer when I’m close to Anna.”
It’s mainly a narrative tool, not a strict mechanical rule. They work like a little mind map of your character’s psychology. By writing them down, you can see how their thoughts evolve during the story, and it helps you get more connected to your character.
There’s no direct mechanical bonus to using them. The only rule is that if you collect 4 permanent thoughts, your character becomes Insane.
I hope this helps, and I wish you enjoy the game!