The Studies Show Tom Chivers and Stuart Ritchie

To be addicted to something, you’ve got to… er, actually, what does it mean to be “addicted” to something? We all agree you can be addicted to heroin, but can you also be addicted to videogames, or sex, or listening to podcasts?
And actually, it turns out we don’t all agree you can be addicted to heroin - or, at least, people have very different models of what that means. In what is effectively an hour-long clarification of a throwaway comment in a previous episode, Tom and Stuart talk through the various aspects of addiction, and try to pin down the scientific definition of what turns out to be a strangely elusive concept.
The Studies Show is brought to you by Works in Progress magazine, whose recent issue covers its usual mix of science, technology, and policy ideas to help with human flourishing. Read deeply-researched articles about prediction markets, gentrification, concrete, and drink-driving policy at worksinprogress.co.
Show notes
* Addiction: A Very Short Introduction, by Keith Humphries
* And his Atlantic article on how de-stigmatising drugs could be a mistake
* Unlocked: The Real Science of Screen Time (and How to Spend it Better) by Pete Etchells
* Scotland’s unbelievably bad drug problem in one graph
* Theodore Dalrymple on Samuel Taylor Coleridge
* And another historical case: The Rugeley Poisoner
* US physician referring to addiction as a “disease” in 1874
* And a German physician discusses “morbid craving” for morphine in 1875
* Made-up Victorian theories on the cause of addiction
* Useful Vaughan Bell article on “the unsexy truth” about dopamine
* Evidence that Parkinson’s patients still experience pleasure despite low dopamine levels
* Evidence that a majority of (UK) smokers want to quit
* The CAGE screening questionnaire for alcohol disorders
* On the 1980 letter cited in and discussed in Dopesick
* Marc Lewis’s Memoirs of an Addicted Brain
* A discussion and critique of the “Rat Park” experiments
* Paper on “Addictive Symptoms of Mukbang Watching” (this is real!)
* The jokey origins of “Internet Use Disorder”
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Should you avoid giving your child peanuts to ensure they don’t develop an allergy? If you’d asked medical authorities this question in the late 90s and early 2000s, you’d get an answer that’s completely opposite to what you’d get now.
In this episode of The Studies Show, Tom and Stuart discuss the science behind the medical recommendations on peanut allergy - the remarkable story of a major scientific U-turn.
The Studies Show is sponsored by Works in Progress magazine. Their latest article, about “advance market commitments” for vaccines and antibiotics and other stuff besides, is now available at worksinprogress.co.
Show notes
* Useful review article on the “diagnosis and management of food allergy”
* Analysis of UK NHS data on hospitalisations and mortality from anaphylaxis
* Two studies raising doubts about parents’ claims that their child has an allergy
* Recommendations on improving tests for food allergy
* 1998 UK Department of Health document recommending not to give children peanuts until 3 years of age
* 2000 American Academy of Pediatrics statement that broadly agrees
* Stuart’s 2023 i article on the controversy
* 2008 observational study comparing Jewish children in the UK (no peanuts) to Jewish children in Israel (lots of peanuts)
* …after which the advice in the UK is announced to be “suspended”
* The 2015 LEAP randomised controlled trial on peanut avoidance vs. peanut consumption in infants
* Follow-up of the same data to age 12
* BBC article about the follow-up
* Observational study from Australia finding no significant change in the prevalence of peanut allergy
* Paper arguing that if we want to see effects, we need to give peanuts to babies even earlier
* The EAT trial of food allergen exposure in non-high-risk infants
* Re-analysis of LEAP and EAT data to work out the best age to administer peanuts
* The PreventADALL study from Sweden
* 2019 article collecting examples of “medical reversals” from across the scientific literature
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Many Western countries, most notably the US, had a major decline in their crime rate in the 1990s. About 20 years earlier, the US had banned the use of lead in gasoline. Perhaps you wouldn’t think those two facts are related - but many researchers think this wasn’t a coincidence.
After getting distracted and doing a whole episode on lead and IQ a couple of weeks ago, Tom and Stuart get to the subject they intended to cover: the lead-crime hypothesis. How strong is the evidence that the presence of lead in a child’s early environment increases their propensity for crime when they grow up? And how strong is the evidence that lead removal (at least partly) caused the declining crime rate?
The Studies Show is brought to you by Works in Progress, the magazine full of new and underrated ideas for advancing science, technology, and humanity. They have a new issue out right now, which opens with a fascinating essay on the decline of drink-driving. Check it out at worksinprogress.co.
Show notes
* Numbers on the US crime rate over time
* Evidence from Finland on IQ and crime
* The first study (to our knowledge) on the lead-crime hypothesis, from 2007
* Rob Verbruggen’s 2021 Manhattan Institute report on lead and crime
* Jennifer Doleac’s 2021 Niskanen Center report on lead and crime
* Paper focusing on 1920s/30s America and the impact of lead on crime
* 2020 Swedish paper on moss lead levels and crime
* 2021 PNAS paper on lead and personality change
* 2022 meta-analysis on the lead-crime hypothesis
* 2023 systematic review on the same topic
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

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Johann Hari is a journalist with an interesting past who has now written four very popular books on scientific topics (addiction, depression, attention, and obesity). Are those books any good?
In this paid-subscriber-only episode of The Studies Show, Tom and Stuart—who have both written reviews of Hari’s books—discuss Hari’s career, his sudden emergence as a science writer, and exactly how many miles you need to travel around the world to ensure your book becomes a New York Times bestseller.

Petrol, pipes, paint: they made a whole generation duller. That’s if you believe the research on the effects of lead on IQ. By interfering with neurological development, the lead that we used to encounter routinely has left hundreds of millions of us with a tiny bit of brain damage.
In this episode of The Studies Show, Tom and Stuart look at the toxic effects of lead - from very obvious, high-dose lead poisoning to the more insidious, low-level effects that have apparently held millions of people back. How strong is the evidence for the effects of low-level lead exposure on IQ?
The Studies Show is brought to you by Works in Progress magazine, a journal of ideas to accelerate human progress. If you’re a student aged 18-22 and want to attend the Works in Progress “Invisible College” this August (at which Stuart is speaking), take a look at this link.
Show Notes
* Centers for Disease Control (CDC) page on lead poisoning
* Articles on the history of lead poisoning from the BBC and the Guardian
* 2022 PNAS study concluding that “half of US population exposed to adverse lead levels in early childhood” (the one with the “824,097,690” figure)
* Article on blood lead levels and which are considered dangerous
* The 2005 meta-analysis on lead and children’s IQs
* Cited in the 2021 “Global Lead Exposure Report”
* The critique from the CDC in 2007
* The critique paper from 2013
* The critique paper from 2016
* The correction from 2019
* The critique paper from 2020
* Quasi experiments: from Rhode Island; using manufacturing employment
* 2018 paper on low-level lead and all-cause mortality
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe

Preventing cancer. Curing depression. Single-handedly ending the COVID-19 pandemic. Oh, and something to do with your bones. Is there anything Vitamin D can’t do?
Maybe the answer is: “quite a lot”. In this episode of The Studies Show, Tom and Stuart look into the claims about the wondrous powers of Vitamin D supplements - and whether any of them have any decent evidence behind them. The whole story turns out to be a perfect parable for how to think about health research.
📚Buy Tom’s book, Everything is Predictable, at this link! And join us at the book launch in London on 16th May 2024! 📚
The Studies Show is brought to you by Works in Progress magazine: the stylish, well-argued, data-packed place to read essays about science, technology and human progress. Find their latest issue at this link.
Show notes
* Rupa Huq MP’s article from during the COVID pandemic on how the government should be “shouting about Vitamin D”
* Huq and David Davis MP convince the government to recommend Vitamin D
* Stuart’s New Statesman article on why this was jumping the gun a little
* How Vitamin D regulates calcium and phosphorus metabolism in the body
* Might it slow tumour growth? Or prevent cardiovascular disease? Evidence from rats
* Observational studies on how Vitamin D levels are related to: depression, cognitive impairment, cancer rates, cardiovascular disease, all-cause mortality
* Review paper claiming widespread deficiency in Vitamin D
* Scientific American article including discussion of the confusion over what it means to be “deficient” in, and/or have an “insufficiency” of Vitamin D
* 2019 paper reporting results from the VITAL trial on cancer and cardiovascular risk
* D-health trial results on cancer risk and cardiovascular risk
* From the D-health trial, papers reporting no effect of Vitamin D supplementation on: cognitive impairment, depression, microbiome diversity, telomere length, hypothyroidism, erectile dysfunction, falls, fractures
* Classic xkcd cartoon on false-positive jelly beans
* 2022 Nature Reviews Endrocrinology review on the (lack of) evidence for the effects of Vitamin D beyond bone-related problems
* Story of UK man who died of a Vitamin D overdose
* Vitamin D and COVID: the promising observational study; the null trial
Credits
The Studies Show is produced by Julian Mayers at Yada Yada Productions.


This is a public episode. If you’d like to discuss this with other subscribers or get access to bonus episodes, visit www.thestudiesshowpod.com/subscribe