The post examines the theory of treating schizophrenia's prodrome stage, exploring how early intervention might prevent full-blown schizophrenia and discussing the biological mechanisms behind the disease's progression. Longer summary

This post discusses the concept of treating the prodrome of schizophrenia, an early stage where symptoms are just beginning to develop. The author explores the theory that early intervention can prevent full-blown schizophrenia, comparing it to early detection in other medical conditions. The post delves into the 'Duration of Untreated Psychosis' (DUP) model, which suggests that psychosis can be toxic to the brain. The author initially expresses skepticism about this model but later becomes more open to it after learning about the biology of schizophrenia. The post then explains a theory of how schizophrenia develops through aberrant prediction errors and how this process might lead to both positive and negative symptoms. It concludes with a first-person account of schizophrenia that illustrates these concepts. Shorter summary

The post reviews research on adult neurogenesis, initially presenting evidence for its existence and importance, then reveals a new study suggesting it doesn't occur in humans, examining the implications of this potential field-wide error. Longer summary

This post reviews the literature on adult neurogenesis, initially presenting numerous studies that claimed to find evidence for the generation of new neurons in adult human brains. These studies linked adult neurogenesis to various aspects of brain function, including memory, learning, and depression. However, the post then reveals a new study suggesting that adult neurogenesis doesn't actually occur in humans, or is so rare as to be insignificant. The author examines how this field-wide error could have occurred, discussing the extrapolation of rat studies to humans and the role of confirmation bias. The post ends by reflecting on the implications of this for scientific research and the replication crisis. Shorter summary

A Links post presenting various news items and articles, ranging from cultural curiosities like the multiocular O to scientific findings about brain sex differences and genetic research, along with commentary on current events and politics. Longer summary

Scott Alexander presents a collection of interesting links and articles covering a wide range of topics. The post includes scientific findings (like research on sex differences in the brain and studies on antidepressants), cultural curiosities (like rare Cyrillic letters), political developments (like the White House's decision on Exxon drilling rights), and various technological advances (like an AI that writes poetry). The post provides brief commentary on each link, often with Scott's characteristically analytical and sometimes humorous perspective on the implications of each item. Shorter summary

Scott shares a diverse collection of links and brief commentaries on scientific studies, political news, cultural phenomena, and personal observations across various fields. Longer summary

This post is a collection of links and brief commentaries on various topics, including scientific studies, political news, and cultural phenomena. Scott covers a wide range of subjects, from the effects of ultraviolet radiation on weight gain to the decline of cults, global inequality trends, genetic links to violent crime, and the concept of competitive governance. He also discusses recent political events, media controversies, and developments in artificial intelligence research. The post includes personal observations, book recommendations, and reflections on social dynamics within online communities. Shorter summary

Scott Alexander examines evidence on marijuana legalization's effects on usage, health, and drug war costs, finding uncertainties too large for firm conclusions but suggesting traffic accidents may be the key factor. Longer summary

Scott Alexander examines the evidence around marijuana legalization, looking at its effects on usage rates, health impacts, and costs of the drug war. He finds that decriminalization and medical marijuana don't seem to increase youth usage much, but full legalization might increase adult use by 25-50%. Health effects are unclear but may include IQ declines and slightly increased psychosis risk. The costs of the drug war are significant in terms of arrests and spending, but relatively few people are in prison solely for marijuana. Scott attempts a utilitarian analysis comparing costs and benefits of legalization, but finds the uncertainties too large to draw firm conclusions. He suggests the most important factor may be how legalization affects traffic accidents. Shorter summary