Is there mental poison too?

I know “poison” is subjective, and I’m not talking about poison that harms or kills(ex: rat poison, cyanide etc.), I’m talking about poison that would effect your brain mentally without physically harming it.

For example, other people’s behaviors, their thoughts, opinions etc. that you’d never think would be in your mind and they’d poison you, not influence you, but poison you. You’d lose your thoughts, your personality would disappear and their thoughts/behaviors start to take over yours.
I’m not talking about the person having to have psychological issues, they could be completely stable.

Whats your opinion? Is there a such thing as mental poison?