"Mental illnesses are disorders of the brain that disrupt a person’s thinking, feeling, moods, and ability to relate to others. Just as diabetes is a disorder of the pancreas, mental illnesses are brain disorders... [They] are not a result of personal weakness, lack of character, or poor upbringing."

That's from a 2000 pamphlet written by the National Alliance for the Mentally Ill. Kandal's claim that this is new is BS - it's an old idea, and one not demonstrated by the research he cites. It's simply more evidence that mental illnesses are mediated by biological processes - something we've known for years.

The claim that mental illnesses are "caused" by biology is just as false now as it was then, and these experiments make no suggestion in either direction.

Clearly, neither study permits inferences about cause. Again, just because biological processes are involved does not mean that it is triggered by it. This is the same idea that's been pushed by over-zealous neuro-scientists for years. It's based on the belief that if we just drill down far enough in biology and genetics, we will explain most of the variance in behaviors.

If you don't cherry-pick the evidence, the whole picture suggests the same story that we've known for quite a while - but some in the psych/mental illness field aren't satisfied with it because the truth doesn't fit with their cravings for prestige - with our cultural obsession with the biological being more "real" than the social. Not to mention the financial aspects - one of the reasons we know so little about the social etiology of mental illness is because there's so little funding available for it.

The evidence suggests that environmental factors are just as involved - and in many cases is the primary cause, which plays on biological vulnerabilities that determine how the illness is expressed and through which it becomes self-perpetuating, not only for the individual, but on down through the family through cultural transmission and epigenetics.

Why does this even matter though? Because our perceptions of mental illness influences its outcome - how we view mental illness determines in large part what it is and how it expresses itself. If we believe it's fundamentally a fixed genetic and biological disorder that the individual themselves is helpless to do anything about, then through the nocebo effect it becomes a self fulfilling prophesy. That is one reason why outcomes for schizophrenia are better in sub-saharan Africa than they are in the US.

Sources

On Epigenetics:
Masterpasqua, F. (2009). Psychology and epigenetics. Review of General Psychology, 13(3), 194. http://pzacad.pitzer.edu/~dmoore/2009_Masterpasqua_Psych&Epi...

On Biological and Environmental Etiology:
Bentall, R. (2009). Doctoring the mind: Is our current treatment of mental illness really any good?. NYU Press. http://www.power2u.org/downloads/Richard-Bentall-Broken-Brai...

Scheid, T. L., & Brown, T. N. (Eds.). (2009). A handbook for the study of mental health: social contexts, theories, and systems. Cambridge University Press.http://hmid.basijmed.ir/public/hmid/books/mental%20health/A_.... 104 to end of chapter provides a good overview)

Whitaker, R. (2011). Anatomy of an epidemic: Magic bullets, psychiatric drugs, and the astonishing rise of mental illness in America. Random House Digital, Inc..

On social Expectancy:
Burns, J. K. The Social Determinants of Schizophrenia: An African Journey in Social Epidemiology. Public Health Reviews, 34(2). http://www.publichealthreviews.eu/upload/pdf_files/12/00_Bur...

Whittaker, R., Kemp, S., & House, A. (2007). Illness perceptions and outcome in mild head injury: a longitudinal study. Journal of Neurology, Neurosurgery & Psychiatry, 78(6), 644-646 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2077969/