The Coming Battle over Serotonin and Depression

Ever since the 1970s, clinicians have been explaining to depressed patients that their problems were owing to “low serotonin,” but that Prozac or Zoloft, famous as selective serotonin reuptake inhibitors (SSRIs), would quickly put things to right. Serotonin became known as the “happiness neurotransmitter,” and drugs that supposedly increased its availability made billions of dollars in pharmaceutical profits. Yes, that’s with a “b.”

But this was never really a scientific story; it was a marketing story. The Prozac-style drugs did well because industry was able to sell the public a scienc-y-sounding tale. And drug ads in the 1990s showed supposed molecules of serotonin as they were scooped back up into the Mother-Neuron, thus producing the happy faces one saw on the next page of the ad: The young women who previously had been stricken with grief were now arm-wrestling with the gang in the bar. The lowered-serotonin story took root in the public domain rather than in psychopharmacology and became an urban myth rather than solid science. (I myself wrote about this in How Everyone Became Depressed: The Rise and Fall of the Nervous Breakdown. Oxford UP, 2013).

There was never any valid scientific evidence showing clinical depression was associated with lowered levels of serotonin: It was all smoke and mirrors. But such is the power of Big Pharma – and such is the power of a good story – that many academics bought into it, and careers were built on the concept of lowered serotonin causing depression.

The leaves had been rustling about this among insiders at psychopharm meetings for decades, and in obscure conference proceedings, expression of dubiety were registered. An important data-driven denunciation of the serotonin myth took place in 2005 (Lacasse JR, Leo J. Serotonin and depression: A disconnect between the advertisements and the scientific literature. PLoS Med 2005; 2: e392 DOI: 10.1371/journal.pmed.0020392. But it did not attract a lot of attention: Everybody knew that low serotonin caused depression. Nobody had time for maverick outliers.

But then the rustling became louder, and a month ago Irish psychiatrist David Healy published in the prestigious British Medical Journal a frontal attack on the serotonin myth so stinging in its scornfulness that many heads turned. Healy said, “This public serotonin was like Freud’s notion of libido—vague, amorphous, and incapable of exploration—a piece of biobabble.” (published Apr 21, 2015 BMJ2015;350:h1771)

Now, a major scientific Donnybrook is looming over this marketing myth. The Brits have always tended to be skeptical about sensational new ideas that crop up on the medical radar, only to fail the test of time. The “hysteria” diagnosis found less favor in nineteenth-century Britain than elsewhere. Freud’s psychoanalysis was largely received with disbelief among British psychiatrists. And even though the Brits were not resistant to the concept of psychopharmacology in general, at the premier English training institute, the Maudsley Hospital in London, social psychiatry was clung to long past its shelf date. (The flip side of this healthy skepticism is throwing the baby out with the bathwater: such unquestionably beneficial treatments as lithium were derided, and British psychiatry on the whole still looks askance at electroconvulsive therapy, ECT.)

So it is unsurprising that some of the dubiety about the serotonin-depression link is coming from such figures as Healy (who although Irish has an appointment in North Wales). The big domes of U.S. psychiatry, by contrast – many of whom have received fortunes from the pharmaceutical industry – continue to assure us that the SSRIs are the drugs of choice for “depression” (as though depression were a single entity).

The serotonin myth will die hard, just as the myth that women were “hysterical” also clenched psychiatry in its death grip right up until the publication of DSM-3 in 1980. But the serotonin myth is on its way out, and the leaves in the Dark Forest are already rustling that entirely too much attention has been paid to neurotransmitters – the brain has, after all, many different ways of managing its internal communication – and that other scientific stories should be granted some of the billions that the U.S. federal government is now bestowing upon research in what is called “mental health.”