This is an amazing Ted Talks by Julia Rucklidge, a clinical psychologist.  She talks about the  various success rates of nutrition, micro supplements and pharmaceutical drugs in treating such things as depression, anxiety, PTSD and ADHD.  Loaded with studies from around the world.

[youtube https://www.youtube.com/watch?v=3dqXHHCc5lA&w=560&h=315]