This editorial, an opinion piece by Prof David Healy, was recently published in the BMJ. In this post I intend to explore the arguments made around whether “chemical imbalance” was ever part of standard medical teaching. I will also explore the suggestion, made by some experts that antidepressant prescribing in the western world is “conservative”.

Professor Healy’s editorial has attracted a number of replies. Here is one:

A psychiatrist in training gave his view that the above reply was “the cleverest” and then offered his own reply:

The psychiatrist in training then gave the following link to what he called: “the sensible reaction”:

I found that I agreed with the statement made in this “expert reaction” by the President of the Royal College of Psychiatrists:

However I found that I did not share the view of Professor David Taylor that the “idea that SSRIs correct an imbalance in the brain never really existed”:

In the 1990’s, as a psychiatrist in training, I followed the “Defeat Depression Campaign”. A central plank of this was the “chemical imbalance theory” involving serotonin. There was hardly an educational event that I went to where a “Stahl” neurotransmitter diagram was not displayed. Even up till 2007, I still found the Stahl diagrams appearing as part of my CME education:

In response to Professor Healy’s article on serotonin and depression it concerns me that experts such as Prof Philip J Cowen and Prof David Taylor are suggesting that the “chemical imbalance theory” always was “mythical”. I was there. It was a very real part of my “education” and often given by experts of the day.

Furthermore, it would seem to me that such expertise is considered as sufficient in itself rather than including experience of taking SSRIs both short and long-term.

In his BMJ editorial Professor Healy gave this stark 2015 statistic:

It has been argued that this figure indicates over-diagnosis:

“Are antidepressant overprescribed”  was the question debated between Dr Des Spence and Professor Ian Reid  published in a BMJ Head-to-Head in January 2013.

A few years before this debate I gave a view on antidepressant prescribing from “my own window” which I submitted as a rapid-response in the BMJ. As I journey through life I often find my views change, but the view from the window I looked out from in 2011 seems still to be very much the same to me.

I was very sad when Professor Ian C Reid died last year, prematurely, as the result of cancer. I trained with Ian Reid in Aberdeen and he was an inspirational speaker and a most committed scientist. His loss is significant.

This research study was published in the British Journal of General Practice in September 2009:

The study gave a conclusion that I agreed with:

The study supported my view that GPs do not indiscriminately prescribe antidepressants. Here, I should be clear, I am talking about newly diagnosed depression, in a time more than a decade on from the likes of the “Defeat Depression Campaign”. However it remains true that access to psychological therapies, in NHS Scotland, remains a very real “challenge”.

Professor Ian Reid went on to say:

And gave his view that:

It is here I depart from sharing Ian Reid’s view. My view is that we need pluralistic evidence, rather than expert opinion alone, that chronic prescribing of antidepressants represents an “improvement in practice”.

The medical profession are generally of the view that long-term antidepressant prescribing is “appropriate” because it is likely that most individuals taking antidepressants have a “recurrent illness” and that such is often demonstrated when they stop taking their antidepressants.

The problem is that most studies into antidepressants, on which prescribing is based, have been short-term studies, often only 6 weeks. Without longer-term studies and the evidence of experience, we simply cannot be sure why so many individuals receive long-term antidepressant treatment.

In summary: It is certainly the case that antidepressants are widely prescribed in the Western world.  In my view we need to see more evidence that prescribing of antidepressants, particularly chronic prescribing, is “appropriate” and “conservative”.

Note to reader:

I am not a "Critical Psychiatrist" as I prescribe psychoactive 
medications including antidepressants. I try to do so only if 
indicated, and if this is the patient's preference. To prescribe 
"appropriately" I do my best to share the knowns and unknowns of 
antidepressant prescribing along with explaining potential harms 
and potential benefits. One potential unknown is the optimal 
duration of prescribing. Professor Reid's evidence would 
appear to demonstrate that long-term prescribing is common 
practice.