For nearly her entire life, Mary had a crippling fear of cramped spaces that meant she couldn’t travel on airplanes, subways, or cars.

Seeing a psychologist didn’t help. So she tried something else. The 61-year-old bookkeeper, who only gave her first name to protect her privacy, sat down in front of a computer and spilled out her problems to a kind of psychiatric computer game called ‘Fearfighter’.