Delving into addiction, the hosts discuss varied interpretations and definitions, exploring behavioral addictions. They touch on historical cases and the evolution of addiction perceptions, from moral to recognized disorders. The conversation also covers addiction research breakthroughs, misconceptions, and complexities like tolerance and dependence.

Discover the evolution of medical recommendations on peanut allergies, from avoiding peanuts in children to early introduction for prevention. Explore studies showing doubts on parental claims of allergies and the impact of peanut consumption on allergy development. Learn about the groundbreaking LEAP trial and the challenges of accurate allergy testing.

Researchers discuss the link between lead exposure in childhood and future criminal behavior, examining the decline in crime rates after the ban on lead in gasoline. Various studies explore the impact of lead on cognitive abilities, personality traits, and crime likelihood, highlighting the complex relationship between lead exposure and criminal tendencies.

Journalist Johann Hari, known for his books on addiction, depression, attention, and obesity, is discussed in this podcast. Topics include Hari's career transition to science writing, controversies surrounding his work, plagiarism accusations, and the complexities of journalism ethics.

The podcast discusses the toxic effects of lead on IQ, highlighting the impact of low-level lead exposure on brain development. It explores the historical use of lead in products and the lingering consequences on cognitive function. The conversation delves into the challenges of quantifying the effects of lead on IQ and the complexities of lead exposure research. The hosts also explore the link between lead exposure and lower IQ levels, emphasizing the need for comprehensive studies and lead removal to prevent health issues.

Vitamin D supplements promises: curing cancer, fighting depression, stopping COVID-19? Tom and Stuart dissect the claims and evidence. The duo explore the controversies around Vitamin D, its benefits, and debunk misconceptions. From bone health to tumor growth, they examine the research on Vitamin D's potential effects on various health outcomes. The episode serves as a cautionary tale on interpreting health research.

Is there really a loneliness epidemic? The health risks of loneliness are compared to smoking 15 cigarettes a day. Trends in loneliness among different age groups are analyzed. The debate on loneliness versus smoking's impact on health is explored. The societal impact of loneliness and the decline of in-person interactions are discussed.

Exploration of the controversy surrounding the Cass Review on youth gender medicine, including the weak evidence for puberty blockers and cross-sex hormones. Discussion on the history and practices of gender dysphoria treatment for young individuals, including therapy and treatment options. Examination of the rise in referrals for gender dysphoria treatments, scrutinizing care quality and waiting lists.

Exploring critiques of traditional depression measurement methods, challenging the concept of a single 'depression'. Analyzing prevalence rates, treatment effectiveness, and brain differences in individuals with depression. Delving into the complexities of measuring depression symptoms and advocating for dynamic evaluations. Emphasizing the need for precise measurement methods and serious research in understanding depression.

Author Tom Chivers discusses probability, historical origins, Bayesianism, and statistical significance in his book 'Everything is Predictable.' The podcast explores the evolution of probability concepts, historical figures like Pascal and Fermat, and the impact of Bayesianism on scientific statistics.