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Comment by ecshafer | Hacker News Reader

If psychotherapy is not a myth, what is the exact mechanism that therapy fixes an issue? If it were science that answer would be readily apparent. I can say exactly how photosynthesis works using chemical structures at every step of the process. But I can’t look up in a book how precisely psychotherapy fixes depression. Psychology has a dearth of actual repeatable testable experiments, which is why it’s not a science.

If so many people lack parenting that gives them the skills to tough it out and deal with it, that psychotherapy is necessary, why were so many people able to function prior to psychotherapy? Psychotherapy is only 100 years old, hell it’s only been socially acceptable for like 20 years. But people functioned just fine.

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> why were so many people able to function prior to psychotherapy?

Were they? If you look at statistics for harmful behaviours like heavy drinking or interpersonal violence, people in the West were absolute basket cases just 100 years ago by current standards. The incidence of such behaviours is much lower today than back then. A general awareness of psychology might be part of it. Not too long ago we were executing soldiers for cowardice after psychological breakdown due to PTSD. Think about how ignorant that is, compared to what we know today.

Anecdotally, mental illness runs in my family. I have the same personality / emotional instability problem almost all males on my father's side of the family have. He did better than most else of ancestors and I've done much better. And I chalk some of it up to psychological awareness of my parents and teachers etc. about how to work with that kind of kid. Good feedback at all stages. I think I would simply have been expelled from school in an earlier era.

> why were so many people able to function prior to psychotherapy

Can you explain why society being able to function prior to psychotherapy contributes at all to considerations about its efficacy and validity to science, or is in any way relevant to discussions about modern science? Walk me through your thought process here, because I'm similarly confused as to why we need all these antibiotics, for humanity survived just fine before they were invented in 1940.

Especially considering:

1) There are many documented cases of mental disorder throughout history that were either poorly-understood mislabeled.

2) Most psychiatric disorders don't have a completely-debilitating effect on those afflicted.

3) The existence of people being able to function does not say anything about the number of people who died/removed themselves from society due to being unable to interact. History is an interesting lens presented only by the people who succeeded enough to produce it.

Would you claim that photosynthesis was a myth if we didn't understand every step of the Krebs cycle?

There are loads of natural phenomena we don't understand precisely, but nature doesn't care. We don't understand how many drugs work. There is no book that explains how thalidomide helps with multiple myeloma but is that a reason to say pharmacology is not science?

Not to be overly pedantic, but the Krebs cycle is a part of respiration, not photosynthesis. Maybe you're thinking of the Calvin cycle?

You are appropriately pedantic. I learnt this in school almost 40 years ago, so apologies. The point still stands, I hope.

It most certainly does, and I didn't mean to detract from it.

Exactly my thought!

It took almost a century before we figured out how photo negatives worked chemically. Didn’t stop anyone from taking photographs though. Mechanistic explanations are great but not a requirement for good science.

> It took almost a century before we figured out how photo negatives worked chemically. Didn’t stop anyone from taking photographs though.

That argument is a strawman as it works with anything that can't be falsiefied.

People who believe in astrology/chakras/etc. will also frequently tell you science will "one day" discover that "it's true". "We're just not there yet."

Also consider what someone may say in a hundered years:

It took almost a century before we figured out that psychotherapy didn't work. Didn’t stop anyone from taking pshychotherapy though. ;)

Psychotherapy presents itself to experimental falsification [1] with epidemiologic studies, whereas astrology/chakras/etc., do not.

(Obviously, Psychotherapy is not a magic-bullet. It is however a valuable health tool to have available, and society should be educated - also on recognizing good and BAD therapeutic practices! - on how to use it, and destigmatized.)

[1] https://www.cambridge.org/core/journals/epidemiology-and-psy...

The basic problem is that you can't do double blind studies. Because the very same person would need to be once treated, once not treated and once treated with a placebo therapy. From the same "baseline brain state".

I.e. you can gather as much data as you want (referring to the metastudy you linked to) but you can't eleminate the inherent bias. People who are treated can not not know they are treated etc.

And while I do believe there is are a lot of forms of psychotherapy that work, I do admit (to myself for that matter) that this is based on belief. Possibly until we can simulate brains with a "sufficient resolution" (whatever that means).

That's not how it works, though.

First, if it is not possible to blind the patient to the intervention and/or provide a meaningful placebo (which also happens with surgery and drugs with prominent side-effects) that's not a big deal, it simply changes the interpretation from "the effect of a particular regime of psychotherapy as such" to "the effect of a particular regime of psychotherapy, including expectation effects". Those expectation effects also exist in real life, if you go to a therapist you really really hope you'll get better and may be motivated to make a few changes in your life independently of the treatment, so if anything the trial becomes more realistic. Note that you'd still use a control arm so that if people get better over time without treatment, you're not exaggerating the effects of the intervention.

Second, almost every randomized controlled trial compares an experimental group against a control group, you are assigned to a group and don't move between them, and what that means is that we can only compare whether the treatment works on average, not whether it worked for one person in particular because, as you say, we don't know what would have happened (counterfactually) if that one specific person had been randomly assigned to the other group. But again, this hardly matters, because we can still know how well a treatment works on average. What you refer to, an experiment in which every subject receives every treatment, is known as a crossover design and while that design has its advantages, it's not that common because it is harder to pull off and while it can be more efficient (need fewer patients to attain an estimate with a given precision) it is not "less biased" or inherently more trustworthy.

> That's not how it works, though.

From the 'Conclusions' of Deaton and Cartwright (2018) [1], which is the one that seemingly comes up in debates among friends most often when this subject arises. I suggest to read that entire part of this paper at least -- it is very sobering. E.g.:

"[...] assumptions that RCTs claim to (but do not) avoid, so that if the aim is to use empirical evidence, any credibility advantage that RCTs have in estimation is no longer operative. And because RCTs tell us so little about why results happen, they have a disadvantage over studies that use a wider range of prior information and data to help nail down mechanisms. [...] Without knowing why things happen and why people do things, we run the risk of worthless casual (‘fairy story’) causal theorizing and have given up on one of the central tasks of economics and other social sciences."

I do not doubt everything in [1] applies even more so to RCTs in something like psychotherapy where the 'success' of 'failure' rests mostly on the interpretation by the subject and the 'why' is a black box. Until we understand and can observe brains in action much, much better and with vastly more detail than we do today that is.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6019115/

The paper you link does not mention anything about the need to try every potential treatment (and no treatment) on every person in a study, and it does not mention anything about any "inherent bias" in RCTs -- these were the two claims you made -- so I'm not quite sure why you bring it up. Given that you have brought it up: I like Deaton's work a lot and know the arguments well, but you have to take into account that in this paper they are trying to provide some counterweight to a hype cycle that suddenly led a bunch of social scientists to argue that observational studies are stupid and should just be gotten rid of entirely and replaced by randomized trials, which for many reasons is not a good idea. That hardly implies that we can never know anything about whether psychotherapy works until we can simulate the brain, that's just a totally bizarre conclusion to draw from that paper.

You can't do a double-blind study with tobacco either. Or geology. Double blind studies are not the only source of knowledge

I disagree: your baseline is a control group (or even the general population). They can answer a questionnaire screening for clinically-significant mental health symptoms (it's not difficult to find untreated people like this), and whether or not they have been to therapy before.

The point is that we can verify whether something works (with a randomized controlled trial) independently of knowing why it works, and psychotherapy interventions are commonly evaluated with RCTs.

The mechanisms are actually quite clear, for example: Psychotherapy frontally tries to get the patient unstuck out of Dysfunctional Behavior and Maladaptive Coping Patterns.

One possible view is that Society has drastically changed in recent generations with industrialization, mass media & consumption, and minuscule families - it used to take a whole village to raise a child.

And to answer your final question, not so long ago, most people also did not know how to read and write, yet “people functioned just fine”.

…does that make mass literacy worthless then?

No, that's just the theory of CBT but there are other theories. Studies apparently shows that several psychotherapy types such as CBT are roughly equally effective despite having different underlying theory.

>But I can’t look up in a book how precisely psychotherapy fixes depression.

Well, you can for CBT. CBT goes by the assumption that a lot of depression comes from negative thoughts and it tries to change the way you think and therefore the way you feel. And CBT is the most scientifically backed up form of psychotherapy. So it looks like that works.

Sure, we don't fully understand the brain yet, but we are making progress.

> Psychology has a dearth of actual repeatable testable experiments, which is why it’s not a science.

Some sciences are characterized by their inability to perform isolated and repeated experiments with identical initial state: Economics, biology, climate, and anything based on humans. They’re still sciences.

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