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Is Depression Really Caused by a Chemical Imbalance?

By Celine Leroudier

A surprising new study published in the journal Molecular Psychiatry recently asserted that “there is no scientific evidence to support the idea that depression is caused by an imbalance of serotonin in the brain.” The researchers further says that, despite that lack of evidence, the public widely believes that low serotonin or chemical imbalances cause depression—and “people are being prescribed antidepressants in huge quantities.” 

In an interview with online biotech magazine NEO.LIFE, however, Columbia Bioethics Program Director Dr. Robert Klitzman disagrees with the study’s conclusion: “Psychiatrists use the term ‘chemical imbalance’ as a metaphor so the public can understand it. It is more accurate to say, rather than an ‘imbalance,’ that something chemical is going on in the brains of people with depression.” 

Klitzman continues by examining the study’s focus on serotonin levels in the bloodstream. If depression is caused by low levels of serotonin in the brain, does it follow that correspondingly low levels of this neurochemical would be found in the bloodstream? “I would argue that depression may be caused by low serotonin levels in the microscopic spaces or synapses between neurons in various parts of the brain, but that such low levels might not necessarily be found in the bloodstream,” said Klitzman. 

Learn more about Columbia’s M.S. in Bioethics program.