Controlling for confounders and demonstrating causality are different things though. They explicitly acknowledge that they don’t demonstrate causality as a stud

Controlling for confounders and demonstrating causality are different things though. They explicitly acknowledge that they don’t demonstrate causality as a study weakness. People who drink alcohol may simply tend to have a slightly different brain structure. In this regard it would be more interesting to see a large scale longitudinal study demonstrating an effect in the same individual over time. Combined with population level studies and a demonstrated mechanism, I think that would be fairly definitive.