When author and Wall Street Journal reporter Andrea Petersen was diagnosed with an anxiety disorder at age 20, she was relieved to finally have a name for the thing that had controlled most of her life to the point where she feared walking up a flight of stairs or standing in line at the store. But understanding and overcoming her anxieties was a different odyssey, one she describes in "On Edge: A Journey Through Anxiety," a memoir she was inspired to write after interviewing college students about their mental health struggles.