Hua CL, Cornell PY, Zimmerman S, et al. - Researchers aimed at ascertaining trends in the prevalence of serious mental illness (SMI) in assisted living (AL) communities over time and as they relate to characteristics such as dual eligibility and health conditions. In addition, they determined within- and between-state variability of SMI in AL. Medicare beneficiaries were used to create samples of those who resided in the 48 contiguous states. Criteria included people who lived in the community, in a nursing home (NH), and in an AL community on December 31 of each year (2007–2017). Observations revealed the rates of SMI in AL increasing from 7.4% in 2007 to 11.4% in 2017. The prevalence of SMI in AL increased at faster pace than the community, but slower than in nursing homes. Substantial between- and within- state variability was observed in the percentage of residents with a diagnosis of SMI. Residents with SMI were more likely to be dually eligible for Medicare and Medicaid vs residents without SMI.