When I was nineteen, a therapist told me she thought I had post-traumatic stress disorder.

"Like a soldier?" I asked, halfway laughing.

She pointed out that I was extremely anxious in our meetings, that I couldn’t sit still, but bit my nails to the quick and glanced around the room and at the closed door. I couldn’t sit with my back to an open window, and I talked as if I had to get the words out quickly, quietly, before someone else heard. That I often looked as if my heart was beating too fast. (It often was.) Hypervigilance, she said.