It is very difficult. Usually my T will ask me if I'm sort of drifting off and that is sometimes enough to pull me back. Other times it is very difficult and I "lose" part of the session. It's hard to stay with the difficult topics sometimes. I try hard to stay present and make myself respond to what my T and I are discussing instead of letting my thoughts only stay in my head. If I stay in my head it's harder to stay present.