The idea that depression is caused by low levels of serotonin and that certain antidepressants raise the levels of this neurotransmitter, is a myth, according to a professor of psychiatry writing an editorial article in The BMJ.

Share on Pinterest The serotonin story has ‘distracted’ us from other biological avenues of understanding depression.

Prof. David Healy – author of the 2004 book Let Them Eat Prozac: The Unhealthy Relationship Between the Pharmaceutical Industry and Depression – argues in the journal’s latest issue that selective serotonin reuptake inhibitors (SSRIs) have never shown any correlation between a potency of serotonin effect and treatment of depression.

Prof. Healy writes that, in the 1990s: “No one knew if SSRIs raised or lowered serotonin levels; they still don’t know. There was no evidence that treatment corrected anything.”

SSRIs are a class of several drugs for mood disorder – they include the high-selling examples citalopram (Celexa), fluoxetine (Prozac and other brands) and sertraline (Zoloft).

The idea that low levels of serotonin are responsible for depression has been “the marketing of a myth” started by drug companies after the 1980s, when concerns had been emerging about tranquillizer dependence. This marketing of SSRIs for depression took place “even though they were weaker than older tricyclic antidepressants.”

The companies “sold the idea that depression was the deeper illness behind the superficial manifestations of anxiety,” Prof. Healy says, describing an “astonishing success” of the approach – “central to which was the notion that SSRIs restored serotonin levels to normal, a notion that later transmuted into the idea that they remedied a chemical imbalance.”