It’s no wonder that many people with PTSD — about 14 percent — try to self-medicate with alcohol. Booze helps us forget, right? The idea lurks in idioms — I might get "trashed" or "wasted," or "drown my sorrows" — and in Proverbs 31:7, and in the gospel of Dave Matthews: Excuse me please / one more drink / Could you make it strong / ‘Cause I don’t need to think… One drink to remember / Then another to forget…

So I was fascinated by a new study showing the opposite. Alcohol, it seems, helps cement painful memories into neural circuits.

On the other hand, the authors note that a separate study suggests that cannabis can help us forget painful memories.