The "Chemical Imbalance" hypothesis is extremely simplistic and seems very appealing to believe amongst the HN crowd. Unfortunately the evidence for it has been sorely lacking and within the past couple of decades more psychologists have been advocating for a wholistic understanding of mental illness. That is it has causes which are complex. It is a mix of childhood experiences, relationships, maladapted development and many other individual circumstances.

Read more here: https://blogs.scientificamerican.com/mind-guest-blog/why-we-...