The chemical imbalance theory has driven much pharmaceutical advertising for psychiatric drugs, such as antidepressants. The research below debunks this old, unproven theory.

A 2005 article documents the way that the pharmaceutical industry used direct-to-consumer advertising to promote the old, unproven theory of serotonin imbalance from the 1960s, even as the current researchers in psychiatry and neuroscience debunked the theory. “Contemporary neuroscience research has failed to confirm any serotonergic lesion in any mental disorder, and has in fact provided significant counterevidence to the explanation of a simple neurotransmitter deficiency.”

In a 2008 study, researchers asked media personalities, who had promoted the chemical imbalance theory, to cite their sources. Most did not cite any sources. Those that did had clearly misunderstood the literature, such as citing articles that explicitly stated that the chemical imbalance theory “was known to be incorrect.”