Estimated Prevalence of Any Mental Illness and Serious Mental Illness Among Adults in the US

"Adults aged 18 or older who were classified as having AMI were further classified as having SMI if they had any mental, behavioral, or emotional disorder that substantially interfered with or limited one or more major life activities. Statistical prediction models that were developed using clinical interview data from a subset of NSDUH adult respondents aged 18 or older between 2008 and 2012 were used to classify whether respondents in the adult samples for 2021 to 2024 had AMI or SMI in the past year. Source variables were statistically imputed for the prediction models used to estimate AMI or SMI.65 

"Among adults aged 18 or older, the percentage who had AMI in the past year showed no change from 2021 to 2024 (Figure 51 and Table A.38B). In 2024, 23.4 percent of adults aged 18 or older (or 61.5 million people) had AMI in the past year. Percentages of adults in each age group who had AMI in the past year also showed no change from 2021 to 2024. In 2024, about one third of young adults aged 18 to 25 (33.2 percent or 11.6 million people) had AMI in the past year. 

"Serious Mental Illness among Adults in the Past Year

"Among adults aged 18 or older, the percentage who had SMI in the past year showed no change from 2021 to 2024 (Figure 52 and Table A.38B). In 2024, 5.6 percent of adults aged 18 or older (or 14.6 million people) had SMI in the past year. Among adults aged 26 to 49 and adults aged 50 or older, the percentages who had SMI in the past year also showed no change from 2021 to 2024. In 2024, 7.5 percent of adults aged 26 to 49 (or 7.9 million people) had SMI in the past year. Among young adults aged 18 to 25, however, the percentage who had SMI in the past year declined from 12.0 percent (or 4.0 million people) in 2021 to 9.4 percent (or 3.3 million people) in 2024."