Runner's World has a very interesting article about the coupling of running and depression as seen through the eyes of (absolutely amazing and inspiring) ultra-runner Lisa Smith-Batchen.
The article discusses how exercise is a natural anti-depressant that has been shown to be more effective than pharmaceuticals. Many people (myself included) rely on running as a mood stabilizer, and it's no secret that when you exercise regularly you feel also better mentally. But... you also tend to feel down and depressed when you stop working out, effectively dropping into an exercise withdrawal. Veeeeeery interesting to see what happens when depression, obsession, addiction, parternity, and endorphins collide within Lisa Smith-Batchen's physique and psyche. It's a crazy upward downward back again spiral that makes you wonder, in spite of yourself, whether running really is a mental illness, and Smith-Batchen needs a re-diagnosis.