I googled "Zinc causes depression" and found your post. I have this same issue. I found out when I was diagnosed with Low T. Doctor wanted me to take testosterone but I at first opted not to and decided to try the supplement ZMA. I noticed a significant change in my moods. Fatigue, angry, depressed, anxious, social anxiety, wanting to just isolate myself from the outside world. Several days after I stopped taking it I went back to my normal self. I have also found out because of this reason I can not even take a multi-vitamin. I spoke with a nutritionist who was baffled by this fact. I was beginning to question my theory about zinc. Glad I found this post and I plan to research more on this topic.
I have never been diagnosed with pyroluria but now may get tested. If you get anymore information please let me know.
Thanks again for the post.