Normal Curves: Sexy Science, Serious Statistics24 Aug

Cannabis and Brain Aging: Can weed keep your brain young?

Can weed protect your brain as you get older? We unpack a study linking lifetime cannabis use to larger brain volumes and better cognitive test scores in older adults—and investigate how those findings became headlines urging readers to “pass the pot to grandma.” Along the way, we explore collapsing categorical variables, confounding, clinically versus statistically significant results, multiple testing, and how a press release subtly changed a story. We also meet permanently stoned mice, learn about Carl Sagan’s surprising connection to cannabis research, and discover how a single missing word can change the entire meaning of a study.

Statistical topics

Categorical variables
Confounding
Effect size
False discovery rate
Healthy volunteer bias
Measurement error
Multiple testing
Observational studies
Recoding variables
Science communication
Statistical vs practical significance

Methodologic Morals

“Always follow the chain from data to result to conclusions and pay attention to the words along the way.”
“Huge samples can give tiny differences delusions of grandeur.”

References

Guha A, Fu Z, Calhoun V, Hutchison KE. Lifetime Cannabis Use Is Associated With Brain Volume and Cognitive Function in Middle-Aged and Older Adults. J Stud Alcohol Drugs. 2026;87(4):739-751. doi:10.15288/jsad.25-00346
Press Release: https://news.cuanschutz.edu/news-stories/study-finds-cannabis-usage-in-middle-aged-and-older-adults-associated-with-larger-brain-volume-better-cognitive-function
Bilkei-Gorzo A, Albayram O, Draffehn A, et al. A chronic low dose of Δ9-tetrahydrocannabinol (THC) restores cognitive function in old mice. Nat Med. 2017;23(6):782-787. doi:10.1038/nm.4311
NY Post: https://nypost.com/2026/02/07/health/cannabis-may-benefit-aging-brains-study-finds/
David Grinspoon: https://www.nytimes.com/2020/07/02/science/lester-grinspoon-dead.html?unlocked_article_code=1.7lA.CyS1.neeqGGNgx8g1&smid=url-share

Kristin and Regina’s online courses:

Demystifying Data: A Modern Approach to Statistical Understanding

Clinical Trials: Design, Strategy, and Analysis

Medical Statistics Certificate Program

Writing in the Sciences

Epidemiology and Clinical Research Graduate Certificate Program

Programs that we teach in:

Epidemiology and Clinical Research Graduate Certificate Program

Find us on:

Kristin - LinkedIn & Twitter/X

Regina - LinkedIn & ReginaNuzzo.com

(00:00) - Opening: The Brain on Drugs
(00:37) - The Cannabis Headline
(03:38) - The Claim: Brain Benefits for Older Adults
(06:53) - The Mouse Study: Pothead Mice vs. Control Mice
(11:25) - From Mice to Humans: UK Biobank
(15:01) - Measurement Problems and Category Collapse
(21:39) - Results: Statistically Significant, Clinically Meaningless
(27:13) - Individual Brain Regions and Cherry-Picking
(32:32) - Cognitive Tests: What Actually Matters
(40:09) - How It Gets Lost in Translation
(45:32) - Rating the Claim

Denne episoden er hentet fra en åpen RSS-feed og er ikke publisert av Podme. Den kan derfor inneholde annonser.

Episoder(45)

Statistical Sleuthing: Can you spot a problem?

Can you spot problems in a scientific study just by reading the published paper? We put our statistical sleuthing skills to the test with a famous study on procrastination and deadlines that was retra...

5 Okt 1h 11min

Ctrl-Z Awards: Will retracting your paper ruin your career?

What happens when you discover that your published paper is wrong? Does retracting it ruin your reputation—or could owning the mistake actually make things better? In this episode, we meet the inaugur...

21 Sep 1h 15min

Statistical Power: When is it useful?

Statistical power is one of the most important ideas in statistics—and one of the most misunderstood. In this episode, we explain what statistical power really means, why researchers need to think abo...

7 Sep 55min

Double Duty: Can the meningitis vaccine also protect against gonorrhea?

Can the meningitis vaccine do double duty against gonorrhea? We examine a fascinating randomized trial inspired by years of encouraging observational studies—and what happened when those earlier resul...

10 Aug 40min

Hot Tubbing: Can soaking in hot water help you run faster?

Can you improve your endurance by sitting in a hot tub instead of doing another hard workout? We dig into a study that put elite runners through five weeks of what we affectionately call “endurance ho...

27 Jul 44min

Exercise Snacks: Can just four minutes of exercise a day improve blood sugar?

Could four one-minute bursts of exercise really improve blood sugar? We try “exercise snacks” ourselves before taking a close look at the clinical trial that inspired headlines. We explain why the stu...

13 Jul 47min

Cancer Blood Tests Part 2: The clinical trial

How do you decide whether a clinical trial “worked”? In Part 2 of our Galleri series, we examine the landmark randomized trial of a blood test designed to detect more than 50 cancers. We explore why d...

29 Jun 57min