> "Repetitive negative thinking (RNT) is a core symptom of a number of common psychological disorders and may be a modifiable process shared by many psychological risk factors that contribute to the development of cognitive impairment." (emphasis added)

This strongly implies that changing negative thinking behavior might reduce cognitive impairment. But the study has no way to establish a cause-effect relationship -- that would require an entirely different kind of study, one that studies the brain, not the mind. In other words, a neuroscience study, one probably not possible at present.

Like many psychology papers, this one implies a cause-effect relationship that isn't supported by the evidence, but one that suggests a role for talk therapy.

It would be interesting to see a review of all modern psychological work, a hundred years from now, from the perspective of a neuroscience that doesn't yet exist, to see how often these articles turned out to be just-so stories with no connection to reality.

A similar finding is that kids who smoke marijuana are likely to experience serious mental health issues later on -- that's indisputable. The problem is the same as in this case -- people assume a cause-effect relationship that isn't supported by the evidence. Maybe kids predisposed to mental health issues are more likely to use marijuana -- that possibility can't be excluded because all the studies are retrospective.

Most people know I can be relied on to make this point, but until neuroscience matures, studies like this will suffer from a theory vacuum. One can only accomplish so much by studying symptoms, with no clue about root biological causes.

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Aurornis 2 days ago | parent [-]

> A similar finding is that kids who smoke marijuana are likely to experience serious mental health issues later on -- that's indisputable. The problem is the same as in this case -- people assume a cause-effect relationship that isn't supported by the evidence.

This is one of those topics where people will set an impossibly high standard for evidence and then use that to reject everything.

We do actually know that heavy marijuana use is associated with increases of mental health conditions. We know that discontinuing heavy use can result in improvements in depression scores over time (following the withdrawal periods which, yes, exists despite decades of people claiming it doesn’t). We know that the increased availability of high concentration THC products has made it worse.

Yet if you want to set your threshold for evidence so high that nothing short of a large scale RCT will answer the question you can ignore all of this, because such an RCT will never be produced for obvious ethical reasons.

This pattern is common in topics where people simple don’t want to believe a casual relationship might exist. I knew a guy who started believing that there isn’t any strong evidence that flossing or even twice-daily brushing were important because he didn’t think the science proved causation that flossing and brushing improved dental health. He believed it was just correlation and people who were healthier in general were also flossing and brushing, coincidentally. His breath was terrible and he later abandoned those ideas when the dental problems undeniably arrived.

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lutusp 2 days ago | parent [-]

> Yet if you want to set your threshold for evidence so high that nothing short of a large scale RCT will answer the question you can ignore all of this, because such an RCT will never be produced for obvious ethical reasons.

Yes, but this means existing studies can't be relied on to justify a conclusion that would have required the impossible study. Saying that a study isn't practical can't be used to justify making a policy decision based on circumstantial evidence.

My use of marijuana studies is meant only to show how bad science steers public policy, not to advocate for its use. There are other, better reasons to avoid that drug.

> This pattern is common in topics where people simple don’t want to believe a casual relationship might exist.

This is why science exists. But if the science cannot be carried out, then we have no right to draw conclusions that would require actual science to be legitimate.

This is moving away from the original topic, which is the kind of sloppy science common in modern psychology, where people wave their hands instead of their scientific results.

> I knew a guy who ...

A red herring, but I think you knew that.

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Aurornis a day ago | parent [-]

> Yes, but this means existing studies can't be relied on…

Exactly my point with this line of thinking: It’s used to argue that you can’t rely on any studies, therefore it becomes a free license to reject everything and inject your own desired conclusions.

	▲	lutusp a day ago \| parent [-]
		>> Yes, but this means existing studies can't be relied on… > Exactly my point with this line of thinking: It’s used to argue that you can’t rely on any studies, therefore it becomes a free license to reject everything and inject your own desired conclusions. The "therefore" section of your comment is your own interpretation, not the reality of a society steered by science. It's why uneducated people believe in Bigfoot. We can't disprove Bigfoot, therefore he exists. It makes a certain kind of pre-modern sense, but it fails to take scientific discipline into account. I'm tempted to call it the Avi Loeb version of cosmology -- we can't disprove the alien provenance of a small distant glowing object, therefore it's an alien craft. And Loeb has a Harvard position on his side -- for those who believe in scientific authority. When confronted by this kind of thinking, I'm reminded of Richard Feynman's remark: "Science is the organized skepticism in the reliability of expert opinion." And finally, it's why psychology has the reputation it does -- many psychologists have no hesitation about leaping ahead of the evidence.