Importance: 2021 Advance child tax credit (ACTC) monthly payments were associated with reduced US child poverty rates; however, policymakers have expressed concerns that permanent adoption would increase parental substance use.
Objective: To assess whether 2021 ACTC monthly payments were temporally associated with changes in substance use among parents compared with adults without children.
Design, Setting, And Participants: The primary sample included adults aged 18 to 64 years who responded to the National Survey on Drug Use and Health in 2021.