About 1 in 5 U.S. adults (roughly 20–23%) experience a diagnosable mental illness each year, while approximately 6% experience serious mental illness (SMI). Let’s break it down:
The National Institute of Mental Health (NIMH) reports that in 2022, around 23.1% of U.S. adults—about 59.3 million—had any mental illness (AMI) in the past year National Institute of Mental Health.
Of these, 6.0% had serious mental illness (SMI), which significantly impairs daily functioning National Institute of Mental Health.
Johns Hopkins Medicine estimates similarly that 26% of Americans aged 18 and older suffer from a diagnosable mental disorder annually Johns Hopkins MedicineThe Zebra.
Alternate phrasing: that’s about 1 in 5 adults with any mental illness and 1 in 20 adults with serious mental illness Verywell HealthNAMI.