Genes for Substance Abuse Has Made No Progress, but Unjustified Optimism Continues

Yet another genetic study of substance abuse:

Using polygenic scores for identifying individuals at increased risk of substance use disorders in clinical and population samples

Highlights:

These PRSs explain ~2.5–3.5% of the variance in AUD (across FT12 and COGA) when all PRSs are included in the same model. 

...usefulness for identifying those at increased risk in their current form is modest, at best 

This was from an all white European sample, ftr, with the assumption that pop strat is accounted for. One can assume, as has been the case, that such pop strat will be found and water this down to next to nothing. That said, is the null 0% or is 2 or 3 % about as low as you can get? I'd be happy to see an example in which a PRS does worse than this.

So is the conclusion that perhaps we are barking up the wrong tree? Of course not:

 Improvement in predictive ability will likely be dependent on increasing the size of well-phenotyped discovery samples. 

The shell game continues...