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Comment by raverbashing | Hacker News Reader

It's just naive to pin something as complex as depression on a single variable (but that's Popperian scientificism for you)

Now it might be that the 1st study identified an effect on a (very specific) subpopulation and in the bigger study case that subpopulation is not present or not identifiable. But who knows

Now of course it's not wrong to study a certain gene, but to go "all in on" a very narrow study path is stupid. Now, if on the course of the depression studies they found this gene had everything to do with a different disease that would be "p-hacking" or something, right? RIGHT?

More statistical power and "rigour" won't lead research anywhere because it's not the studies that were necessarily flawed, it's that the effects might be small, or dependent on a chain of other factors, so unless the effect of a single factor is predominant it might not even matter (as an isolated factor).

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Thinking that a single gene could cause depression isn't fallacious - pinning all depression on it would be.

But a single gene as a possible cause isn't surprising given other more extreme single gene effects with other cognitive and developmental effects - angelman syndrome is marked for its cheerfulness and niceness.

If you were seeking such a gene you would search for anomalous histories of suicides in a family tree.

>It's just naive to pin something as complex as depression

No it's not. Twin-based heritability studies show depression risk has about 10% heritability across all cases and 50% heritability among severe cases. There is a genetic component to the disease.

That complexity is mediated by dozens of genes, but each one gene contributes a percentage to that heritability. Single genes can and will be found which link genotype to phenotype. It is just a matter of time and money.

You don't think you're mixing up "heritable" with "genetic" here? In my family, liking the Yankees is highly heritable across generations, but my grandfather would've laughed in your face if you claimed it was genetic.

>You don't think you're mixing up "heritable" with "genetic" here?

"Heritable" in this context is a term of art. It is a statistic (H squared) that describes the amount of a phenotype that is transmitted from generation to generation. This value broadly describes the amount of a phenotype which can be ascribed to genetics compared to environment without linking it to any known genes or genomic elements. It is a classical technique that was primarily used before we were able to sequence DNA. This is usually figured out by using "twin studies" which are able to quantify inheritance by comparing two individuals with the same genetics.

https://en.wikipedia.org/wiki/Heritability

> that's Popperian scientificism

I believe his criticisms would be very close to yours. For me, this is on the border between medicine, anthropology and in general social sciences. I wouldn't list hubris as a strength for anyone in these fields to underline popular prejudices.

But aside from that, even if statistics are vigorously checked for correctness, it still leaves a lot of room to get different interpretations.

>It's just naive to pin something as complex as depression on a single variable

Why? There are other complex diseases with purely genetic causes, e.g. Huntington's Disease; depression isn't necessarily different. Hindsight is 20/20.

Yes, but Huntington's is an explicit cluster of symptoms at diagnosis + a specific prognosis. Uppercase D "Depression" is a diagnosis built around a single symptom, lowercase d "depression". But many people experience depression, both in "core mental illnesses" like bipolar and outside. (Note how bipolar is much better constructed -- indeed the method of differential diagnosis was invented by Kraepelin to differentiate bipolar from schizophrenia)

If it was up to me, big D Depression would be redefined as "responds to Prozac" or something.

Huntington’s is a very precisely defined disease. Depression has a much wider range of manifestations.

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