Last week, we blogged about recent coverage of the serotonin theory by NPR, which discussed the falsified status of the serotonin theory. We are happy to see that good information is now reaching the general public. However, there was a related (and perhaps even more important) issue discussed in the interview that we address below:
The scientists on NPR discuss the fact that we now know that depression is much more complex than a simple serotonin imbalance. One guest describes the serotonin story as “late 20th century thinking.” Listening to the show, you get the impression that the serotonin theory was a viable contender just a few years ago; as of 1999, for instance, a psychiatrist telling her patients that they suffered from a serotonin imbalance would have simply reflected the current psychiatric thinking; and only recently have we learned that it’s much more complicated than this…
But what if this isn’t true? What if research has indicated for decades that the serotonin theory is false, yet psychiatrists told their patients the serotonin story anyway? What would this mean?
Here are a collection of selected material from books and articles covering the evolution of the serotonin theory. Pay attention to the year:
“By 1970…[George] Ashcroft had concluded that, whatever was wrong in depression, it was not lowered serotonin.” [D. Healy, Let Them Eat Prozac]
“…the biogenic amine theory [serotonin, norepinepehrine, dopamine] now more closely resembles a venerable flag than a tool we can work with…” [Bernard Carroll, 1982, cited in Before Prozac by E. Shorter].
“The simplistic idea of ‘the 5-HT [serotonin]’ neurone does not bear any relation to reality.” John Evenden, Astra pharmaceutical company research scientist, 1990 [See Before Prozac by E. Shorter].
1991: The antidepressant drug tianeptine lowers serotonin but is found to be an effective antidepressant [See Chamba et al., 1991]
Psychiatric historian David Healy argues that the serotonin story is a marketing ploy, 1997 [See D. Healy, The Antidepressant Era]
“Although it is often stated with great confidence that depressed people have a serotonin or norepinephrine deficiency, the evidence actually contradicts these claims.” [Neuroscientist Elliot Valenstein, 1998, in Blaming the Brain]
"In truth, the "chemical imbalance" notion was always a kind of urban legend- never a theory seriously propounded by well-informed psychiatrists." Ronald Pies, M.D., Editor of Psychiatric Times, in 2011
By the late 1990s and early 2000s, the scientific data on the serotonin theory was not only available to psychiatrists, but there were a series of popular-press books pointing out the problems with the theory, largely driven by experimental data from studies performed from the 1970s to 1990s. It seems reasonable to assume that practicing psychiatrists were just as informed about serotonin as members of the general public who read a book like Blaming the Brain or The Undiscovered Mind. Our current discussions take place 14 years after the publication of Blaming the Brain, and at least 20 years after scientific data showed clear problems with the serotonin theory.
By 2006, Wayne Goodman, M.D., the chair of the FDA Psychopharmacological Advisory committee, had publicly conceded that the serotonin theory was but a "useful metaphor" - and one he never used in his own interactions with patients.
Yet, here in early 2012, the fact that the serotonin theory has been falsified is newsworthy and, in our experience, often surprises people.
What does this say about the state of psychiatric science and practice?
Is this simply the slow march of scientific progress, or is something else going on here?