Associations.

The moment you see a blade and your first thought is cut.
The moment you see a flame and your first thought is burn.
The moment you're up high and your first thought is jump.
The moment you see medicine and your first thought is how many it would take to overdose.
The moment you are in a crowded room and your first thought is I'm all alone.
The moment you wake up and your first thought is I can't take this anymore.