Arrow, that is also great info. I agree that feeding people drugs forever is not the best option. There are so many potential causes for depression, as well as helpful natural treatments, which I try to write about as much as I can.
As for hormonal causes, I know that my issues are heavily affected by my hormones. I have premenstrual dysphoric disorder (PMDD), and though my periods are somewhat irregular, I (as well as everyone around me) know that my period is coming because for about a week and a half, I have little control over my emotions. I sob, I scream, I get extremely angry, and I feel completely hopeless. It's such a rollercoaster ride...AND I HATE ROLLERCOASTERS!!
Thanks for the information regarding the serotonin in the gut. I wasn't aware of that.