Im looking for a horror novel that’s not hard to read

I started to read books as my girl got me into it. She’s into psychological novels while I want a horror/psychological on it. For now I’m reading edgar allan poe’s mystery of tales and imaginations as well as lovecraft’s works. I want a novel thats easy to understand while mind bending can anyone suggest me some?

Edit: you can also suggest me some books that’s psychological since I’m planning to buy her one as well. Books she have already read are No longer Human, Crimes and punishment, picture of dorian gray, and white nights (all i can remember)