More than 20% of US young adults struggle to fall or stay asleep.1 Cannabis and alcohol can help initiate sleep,2,3 but regular use may be problematic.4 Increasing tolerance can lead to greater use to produce consistent sleep outcomes, potentially contributing to use disorder and sleep problems.2 Young adulthood is a critical developmental period for both substance use risk and sleep problems, underscoring the need for national data on cannabis and alcohol use for sleep.5,6