Thread by @GidMK

This is unholy nonsense of the highest order:

- n=92
- over a dozen uncontrolled t-tests
- NO DIFFERENCE BETWEEN PLACEBO AND CONTROL
- headline findings based on sub-group analyses
- fish oil does bugger all for ADHD

Study is here: nature.com/articles/s4139…

Basically, the researchers gave fish oil or a placebo to kids with ADHD for 12 weeks, and tested them on a range of cognitive processing tasks before and after

Here's their statistical analysis. If this reads like "we threw t-tests at a range of variables until results came out", to you, I'd say your not alone

The main findings of the research?

I'll just let the results table speak for itself. I think it does a brilliant job all by itself

JUST LOOK AT THIS

A dozen statistical tests. Two 'significant' p-values (with one going in the OPPOSITE DIRECTION i.e. fish oil is bad)

Pretty much what we'd expect if there was no difference whatsoever

All of the headlines were based on this - a subgroup analysis comparing only children with low baseline levels of EPA

In other words, in the tiny subgroup (~30 children) who started off with low levels of fatty acids in their blood, there was a tiny indication that fish oil might be of some modest benefit

NOT VERY IMPRESSIVE IS IT

Also, these headlines saying that "fish oil might be as useful as drugs" are total trash

THE STUDY DIDN'T LOOK AT DRUGS AT ALL

The talk of drugs appears to be based on a quote from one of the authors of the study, which is astonishing given that the study didn't look at fish oil in comparison to drugs

Also, the study doesn't report excluding kids who were on drugs at the start of the trial, so it's likely that some of the differences could be due to drugs anyway...

Also, did I mention the trial used a per-protocol analysis? I should definitely mention that

So, in other words, with a design known to bias results, dozens of uncontrolled statistical tests, and still THE MAIN FINDINGS WERE NEGATIVE

TL:DR

- main findings were negative
- no benefit to fish oil
- nothing to do with ADHD drugs

Blog now up on this link.medium.com/s5YLwEDeO1