I too have struggled with depression ever since puberty occurred in the wrong body, sometimes going several months without functioning in life and considering suicide as well. Aside from food, estrogen is the only thing that has ever been able to stop me from falling back into the darkness. When I tried to add progesterone (at the recommendation of my doctor to block testosterone, since I could not handle the side effects of spironolactone), I became awfully calm. All of the emotionality I had gained from the estrogen, so essential to being my true self, was gone, and I felt really sad. Fortunately, I got off the progesterone before it became full-blown depression, and my mood returned to normal within a day after stopping the progesterone. The bio-identical progesterone was what brought my mood down. MPA had a somewhat different effect on my mood, causing moderate anxiety and mild aggression rather than the depressive effect of progesterone. Both of them also interfered with the estrogen to the point at which my body (face and measurements) actually masculinized while taking them. Both of my doctors admitted that depression can be a side effect of progesterone, and my first doctor was so worried that he did not want to prescribe it; he had seen it happen in other trans women.