Recently, Moncrieff et al’s paper “The serotonin theory of depression: a systematic umbrella review of the evidence” made headlines. You can read it for yourselves, it’s open access.

I was inspired to write this blog post because of all the headlines and social media discussions that followed, but I won’t discuss serotonin or depression in particular. Rather, I will distinguish different questions one might ask about psychiatry and psych drugs from each other; discussions become muddled if we assume that it’s all about being “for” or “against” medication, or if one “believes in” psychiatric conditions or not.

Question 1. What evidence do we have for underlying brain dysfunctions?

Do we have evidence that this or that psychiatric or neuropsychiatric condition is caused by or constituted by a particular neurotransmitter imbalance or other brain dysfunction? (Causal claims are often not distinguished from constitutive claims in popular writings, but I’ll stick to “caused by” from now on for the sake of simplicity.)

Here, the answer is “no” pretty much across the board. We might have somewhat better supported hypotheses for some conditions than others, but we have no firmly proven theory about anything. (Yes, this is so despite all the popular psychology articles and popular social media memes that indicate otherwise.) Optimistic and biologically oriented psychiatrists have believed for over a century now that the Big Scientific Breakthrough, when we manage to pin down the underlying neurological abnormalities for each psychiatric diagnosis, is right around the corner, but so far, they’ve been wrong. (My guess is that there’s no such breakthrough coming within my lifetime either.)
The fact that a drug designed to increase serotonin levels make people feel less depressed does not, in itself, constitute particularly strong evidence that the problem was caused by too little serotonin in the first place – the fact that paracetamol stops headaches doesn’t mean that headaches are caused by a paracetamol deficit. The same goes for all reasoning from the effects of drugs to causes.

Sub-question 1.1. But… but… physicalism!

Isn’t it obvious that there must be an underlying brain dysfunction for every psychiatric issue? I mean, what’s the alternative? That all those mental problems reside in some immaterial soul?

No, and no. First, even philosophers who believe in immaterial souls, most famously Descartes, didn’t conceive of the soul as independent of the brain; he thought they interacted all the time. He knew, for instance, that when someone gets drunk (that is, they affect their physical brain by ingesting a physical substance), their thoughts and emotions are also affected. So regardless of your mind/body/soul beliefs, it’s completely obvious that all mental events (thoughts, emotions, etc) must consist in or at least correspond to to brain events.

However, this doesn’t guarantee that we will ever find the same systematic and measurable brain dysfunction in everyone who’s got similar mental problems. (See my colleague Anneli Jefferson’s great book Are Mental Disorders Brain Disorders? For a more thorough discussion.)

Sub-question 1.2. Shouldn’t people stop complaining?

If we can’t find underlying neurotransmitter imbalances or other brain dysfunctions in people with various psychiatric and neuropsychiatric conditions, does that mean that they should just stop complaining, because there isn’t actually anything wrong with them? No, that doesn’t follow at all. I’m not even sure how to argue against this idea, because it’s so irrational.

Sub-question 1.3. Is everything reducible to trauma?

But surely it follows, some “anti-psychiatrists” say, that if we can’t find any underlying brain dysfunctions, it means that the only difference between so-called disordered people and others are that the former are traumatized? No, that doesn’t follow either. There is ample research to demonstrate that trauma plays an important part in the development of many psychiatric conditions, but that doesn’t mean that there are no important mental differences between people – how they think, how they feel, how they perceive the world, etc. – except for whether they’re traumatized or not.

Question 2: Are the drugs efficacious?

Do we have evidence that this or that drug really helps with this or that problem? Well, the state of evidence looks different for different drugs. The efficacy can also differ between the short term, a few months or a year, and the long term, several years or taking the drug for life. To further complicate the matter, people with the same diagnosis can differ sharply in how they respond. See above: we don’t know if there is even the same underlying brain dysfunction in everyone with the same diagnosis, but likely not, since psychiatric diagnosis have notoriously low reliability (i.e., different psychiatrists will diagnose the same patient differently).

If one wants to know whether a certain drug has an effect beyond placebo, at least in many people if not all, one should look for studies that

a) feature a placebo control group, that

b) didn’t have their previous medication abruptly switched for placebo when the study began (if so, they might get withdrawal symptoms which distort the result),

c) were properly double blind, which

d) ideally requires that an active placebo is used (e.g., an appetite enhancing pill).

Many people (and even doctors!) say that they know from their own experience that some drug has an effect that goes way beyond placebo, but that’s just nonsense. The reason we do studies with placebo control groups in the first place is precisely that there isn’t “a placebo feeling” which is different from a “the drug is really working feeling”.

Question 3. Is it bad to take psych drugs?

Is it somehow morally bad to take psych drugs? Does everyone have an obligation to instead deal with their problems by talk therapy, or perhaps with yoga, exercise and kombucha?
Well, as a moral philosopher specialized in the philosophy of psychiatry, let me tell you from the bottom of my expertise that the answer is “no”. If that mere appeal to authority wasn’t sufficient to sway you, I will elaborate.

It’s not always easy to access talk therapy, even if cost isn’t an issue. It’s important to find the right therapist, which isn’t always an easy feat. Even if you do, there’s no guarantee that you will make a full recovery, whatever that means.
Furthermore, you might suffer so much that you need relief here and now. You might also suffer so much that you must get some initial improvement before you can muster up the mental strength to talk about your distress, or the motivation to exercise and improve your overall lifestyle. (I’ve seen lots of people mock the idea that exercise could improve mental health as pseudoscience, but it’s not; there’s plenty of research on exercise and depression, for instance. Still, that same depression might very well prevent you from muster up the motivation needed to exercise, if you’re a regular depression patient and not part of a research study with scientists that prompt you to follow the program.)

Finally, setting all of the above aside, we should ask why it would be wrong in principle to “take a short cut” to better mental health if a short cut is available. People take the easier route all the time without being blamed and shamed for it. Off the top of my head, I buy most of the food I eat in the grocery store, instead of turning my entire yard into a farm and growing it myself, and there’s nothing wrong with that. Right now, I write a blog post instead of printing out physical pamphlets that I then snail-mail to everyone who seems interested.

Question 4. Are people over-diagnosed now, or were they under-diagnosed in the past?

Are people today over-diagnosed, or were people in the past on the contrary under-diagnosed? This is a false dichotomy. It’s possible that we’ve had the right number of diagnoses all along, even though it’s sharply risen (I’m not saying that’s the case, just that it’s possible).

If condition X is mostly brought about by trauma, stress or the like, then it’s possible that some time periods are more traumatic or stressful than others, and therefore give rise to more people with X. (When people say “but surely society gets better and better over time, so surely people growing up today have it better than ever”, I always point out that it’s increasingly hard to get your own place to live and move away from home, and that’s very important for kids from abusive households. There’s the rise of “gig jobs” instead of secure and sufficiently well-paid employment, and there’s plenty of research on how big an impact constant stress has on mental health. Not to mention the rampant climate crisis, with no turning point in sight.)

If condition Y is something you’re born with, it’s still possible that more people need a diagnosis in some time periods. Pretty much all conditions exist on a spectrum. There might be people with Y who come off as distinctly odd and have a hard time managing what’s considered “a normal life” regardless of time and culture, and other people who are always seen as “normal”, but then there are those who might or might not manage without extra help, and might or might not come off as odd, depending on the time, place and culture they live in. If more and more people receive diagnosis Y over time, it might be because society changes in such a way that this “middle group” becomes increasingly stigmatized and increasingly in need of special accommodations.

Furthermore, two problems might exist simultaneously in the same system: There could both be people who have ordinary reactions to stress, abuse etc., and are needlessly pathologized and medicated, when all they really would have needed was getting out of their current situation and some love and understanding, and people who have their very serious struggles and distress brushed off with a “we all feel like that sometimes” and don’t get taken as seriously as they should. One doesn’t preclude the other.

Finally, it is a serious problem that psychiatric conditions are so often seen as “all in the head”, all about the individual person’s brain, and that too little attention is paid to how things like intense and never-ending job stress, being forced to live with people who abuse you, poverty, racism, and so on contribute. There is no lack of research about all this, but it’s often forgotten in public debates about mental health. We could plausibly improve average mental health in the entire population by making sure that there are enough apartments for everyone, that everyone have livable wages without working overtime, that people have secure employment instead of gig jobs, that disability pensions and health insurance for people on sick leave are livable, and so on.
If we did all that, predictably, fewer people would need a psychiatric diagnosis, so in that way, too many people are diagnosed nowadays. However, that does not mean that psychiatrists and other mental health personnel should begin to dismiss people who seek help, because in the actual society we live in, they likely need it.