Scott Alexander discusses a study challenging the idea that childhood abuse lowers IQ, and explores its implications for understanding the effects of child abuse on various outcomes. Longer summary

This post discusses a study by Danese et al. challenging the assumption that childhood abuse lowers IQ. The study found that after adjusting for pre-existing factors, there was no significant difference in IQ between abused and non-abused children. Scott Alexander explores the implications of this study in the context of shared-environment-skeptical psychiatry and discusses other studies showing limited effects of child abuse on various outcomes. He notes that while these findings are interesting, they may understate the dangers of severe abuse due to sample size limitations. The post concludes by suggesting that child abuse likely causes PTSD-like symptoms but may not have effects drastically different from normal PTSD. Shorter summary

Scott Alexander examines a study showing positive effects of early intervention on at-risk children, but questions its policy implications due to high costs. Longer summary

Scott Alexander discusses a study on early intervention programs for at-risk children, which showed positive effects on various outcomes at age 25. The study, a randomized controlled trial, found that intensive interventions costing $60,000 per child reduced the odds of developing psychiatric disorders, substance abuse problems, and engaging in criminal behavior. While the results are scientifically interesting, Scott points out some limitations and questions the cost-effectiveness from a policy perspective. He notes that the intervention didn't affect all outcomes equally and that the high cost might not justify the benefits when compared to existing educational spending. Shorter summary

Scott Alexander examines studies linking parental age to psychiatric disorders in children, revealing that the father's age at first child, not at conception, is the key factor. Longer summary

Scott Alexander discusses a study in JAMA Psychiatry about the prevalence of psychiatric disorders in relation to parental age. Initially, it seemed that children of young mothers and old fathers were at higher risk. The study proposed that older fathers accumulate more mutations, leading to higher risk of disorders in their children. However, a clever follow-up study found that the risk is more related to how old the father was when he had his first child, rather than the father's age at conception. This suggests that men with mental health issues or risk factors may take longer to find partners and have children, rather than the age itself being the cause. Scott concludes that this finding is sad on a societal level but personally liberating, as he feels less guilty about potentially having children later in life. Shorter summary