Eight months ago, I sat in my office, tears gathering in my eyes. "Not again," I said aloud to myself. "Not here." I blinked back the wetness in my eyes and tried to focus on my computer project. No luck. More tears. With a deep breath I headed for the ladies room, trying to keep my composure until I was safe within the privacy of a stall. Once inside I let the tears spill, dabbing them carefully with toilet paper. Sadness welled up from deep inside, snuffing out my normally upbeat personality. Why can't I keep my emotions under control? I wondered in frustration and embarrassment.

This scenario had become all too familiar in the last several months. I'd be enjoying a perfectly fine day only to be unexpectedly overtaken by sadness or hopelessness. Some days I even awoke feeling sad. These emotions usually overwhelmed me when I was alone—in my car, in my office, in my bed as I tried to fall asleep. While I'd always been an emotional person, this was different. I couldn't find any apparent ...