US National Spending On Mental Health And Substance Use Disorder Treatment Driven By Case Growth, 2000–21

Understanding what the US spends to treat mental health and substance use disorders (SUD) is important for understanding spending patterns and informing health policy. In this study, we determined that from 2000 through 2021, mental health and SUD nominal spending grew from $40.9 billion to $139.6 billion. Mental health and SUD accounted for 4.5 percent of all medical services spending in 2000 and 5.5 percent in 2021. Real per capita mental health and SUD spending grew at an average annual rate of 3.27 percent, which was faster than the growth rate for overall medical services (2.21 percent). Our decomposition analysis showed that mental health and SUD spending growth was driven primarily by increases in the number of people receiving treatment (representing 87.3 percent of the growth) and to a much lesser extent by increases in the cost per case (12.7 percent of the growth). However, because disease severity was unobserved, these patterns may partly reflect increased treatment of less severe cases rather than unchanged severity-adjusted treatment costs. During this period, the number of mental health and SUD cases treated grew by 253 percent. In contrast, for spending increases on all diseases, 66.3 percent of the total spending growth resulted from increases in cost per case, and 33.7 percent resulted from more people receiving treatment.