Keith Humphreys, Stanford University: China’s supply shock of fentanyl and chemical precursors

Keith Humphreys, a leading expert on addiction psychiatry, based at Stanford University, unpacks his January article in Science examining the steep reduction in overdoses deaths—between May 2023 and the end of 2024—in the United States and Canada. It likely stemmed from a supply shock, linked to steps taken by China to disrupt the supply of fentanyl and precursor chemicals. Underneath, US-China diplomacy was essential. This story was lost during the 2024 US presidential election cycle. Subsequently, President Trump’s overt threats to China, including the imposition of a 20% tariff tied to fentanyl, changed the negotiating context. Some progress followed on October 30 when Presidents XI and Trump met on the margins of the APEC summit in South Korea.