Continuous and Enduring Action to Stop Every Overdose Act of 2023 or the CEASE Overdose Act of 2023 This bill permanently places fentanyl-related substances as a class into schedule I of the Controlled Substances Act. A schedule I controlled substance is a drug, substance, or chemical that has a high potential for abuse; has no currently accepted medical value; and is subject to regulatory controls and administrative, civil, and criminal penalties under the Controlled Substances Act. The temporary scheduling order issued by the Drug Enforcement Administration to place fentanyl-related substances into schedule I of the Controlled Substances Act expires on December 31, 2024.