as one of those last try things, after therapy and medication, lifestyle and social life change etc. (ie conventional advice) sure. Or I think it needs a lot more research to show it's safer than antidepressants which is not entirely without side effects but if that doesn't work sure. Even electroshock is one of those last try things I guess, but the mushrooms are probably safer as ETC is not safe, ketamine maybe too. I just say if people are driven to want suicide by socially constructed circumstances (not inborn depression or being end of life) it says nothing good about society and it is a social problem.
Pollan's always been a good writer, some of the books were just meant as quick guides (for the nutritionally confused who were too lazy to read Omnivores Dilema) though and I'm sure quite profitable, and not real books, so one isn't going to enjoy his writing style there. Pollan's lasting and ironic impact there was probably just to get people to eat more meat, although grass fed.