Does cannabis protect the aging brain—or are we watching correlation quietly turn into causation?

In this episode of LSAT Logic Applied, Andrew Leahey breaks down a newly accepted study from the Journal of Studies on Alcohol and Drugs titled “Lifetime Cannabis Use Is Associated with Brain Volume and Cognitive Function in Middle-Aged and Older Adults.”

Using UK Biobank data, the study finds that lifetime cannabis use is associated with larger brain volumes in certain regions and better cognitive performance later in life.

But association is not explanation.

Applying LSAT Necessary Assumption analysis, this episode shows how scientific findings—carefully written and caveated—can be misread once assumptions about causation, directionality, and confounding factors sneak in. Learn how to spot the unstated premise holding the argument together, and why negating it causes the explanation to fall apart.

You don’t need to be studying for the LSAT to follow along—this is about learning how real-world arguments work, and where they quietly overreach.

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