Since there is no evidence to link low-serotonin levels to depression.

This chemical imbalance story, countlessly repeated on antidepressant commercials and by psychiatrists from prestigious institutions, has been so effective that it comes as a surprise to many Americans—including Alix Spiegel— to discover that the psychiatric establishment now claims that it has always known that this theory was not true or “urban legend,” the term used by Ronald Pies, Editor-in-Chief Emeritus of the Psychiatric Times. Pies stated in 2011, “In truth, the ‘chemical imbalance’ notion was always a kind of urban legend—never a theory seriously propounded by well-informed psychiatrists.”

Truly well-informed psychiatrists have long known that research showed that low serotonin (or other neurotransmitter) levels were not the cause of depression. The American Medical Association Essential Guide to Depression in 1998 stated: “The link between low levels of serotonin and depressive illness is unclear, as some depressed people have too much serotonin.” But the vast majority of Americans—who didn’t read this textbook—never heard this.

http://www.counterpunch.org/2014/05/14/psychiatrys-manufacture-of-consent/