Genes associated with addiction and impulsivity are polygenic and most highly expressed during neurodevelopment in the second and third trimesters of gestation.

“So, I'd be very curious to know what those genes encode for. But what are the protein systems and neural circuit systems, hormone systems downstream of those genes? ... So what we found is that there's many many many genes that affect all of these behaviors. It's massively what we call polygenic. So it's not just one thing in one part of your genome. It's distributed throughout your genome. And that those genes are most expressed in neurode development in uterero in second and third trimester.”