One adult in five has a mental illness by the federal count, and the number has not moved since 2021
SAMHSA's 2025 survey puts any mental illness at 20.6% of adults, serious mental illness at 6.9% (down from 7.9%), and a major depressive episode at 7.4% (down from 8.5%). Every decline is concentrated in 18 to 25 year olds.
We have not finished checking this source. No judgement either way. how we score evidence
Caveat on this rating: NSDUH surveys the civilian, noninstitutionalized population aged 12 or older, so people in hospitals, prisons, nursing homes, on active duty or unsheltered are not in it; SAMHSA states that estimates from 2021 onward are not comparable with 2020 or earlier, so no line here runs back further than 2021. A survey answer is not a diagnosis. 'Any mental illness' and 'serious mental illness' are model estimates calibrated on clinical interviews, not counts of diagnoses.
Significant findings
The 2025 National Survey on Drug Use and Health completed 60,447 interviews, 49,514 of them with adults. Its headline mental health numbers come in three sizes.
Any mental illness, the broadest, is estimated by a statistical model from a short distress and disability scale rather than asked directly. The report's table gives 21.0, 21.3, 20.9, 21.5 and 20.6 percent of adults for 2021 to 2025. Among 18 to 25 year olds it ran 33.2 percent in 2021 and 28.6 percent in 2025.
Serious mental illness is the subset the model predicts to have serious functional impairment. The report: "Among adults aged 18 or older, the percentage who had SMI in the past year decreased from 7.9 percent (or 20.1 million people) in 2021 to 6.9 percent (or 18.2 million people) in 2025 (Figure 64 and Table A.44B). Among young adults aged 18 to 25, the percentage who had SMI in the past year also decreased from 16.8 percent (or 5.6 million people) in 2021 to 12.1 percent (or 4.4 million people) in 2025. Among adults aged 26 to 49 and adults aged 50 or older, however, the percentages who had SMI in the past year showed no change from 2021 to 2025."
A major depressive episode is asked directly, through interview questions matched to the diagnostic criteria. The report's table: adults 18 or older 8.5, 8.8, 8.5, 8.2 and 7.4 percent; 18 to 25, 19.3 to 14.2; 26 to 49, 9.6 to 9.1; 50 or older, 4.5 to 4.0. Severe impairment among adults fell "from 5.9 percent (or 14.9 million people) in 2021 to 5.2 percent (or 13.8 million people) in 2025", and among young adults "from 13.8 percent (or 4.6 million people) in 2021 to 10.2 percent (or 3.7 million people) in 2025." Among 26 to 49 year olds the severe figure "showed no change."
Treatment is published for 2025 only: "Of these adults with a past year MDE, 65.9 percent (or 13.0 million people) received any of the types of mental health treatment in the past year."
Worth asking
Three different numbers answer "how many adults have a mental illness": one in five, one in fourteen, one in thirteen. They are different questions, not different opinions. The survey reaches households, dorms and shelters, and not hospitals, prisons or the street, so the people most likely to be severely ill are the ones it cannot count.
Source
Key Substance Use and Mental Health Indicators in the United States: Results from the 2025 National Survey on Drug Use and Health (full report PDF) — Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality (2026)
How this was scored
- Study design
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- Published in
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- Sample size
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- Preregistered
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- Conflicts disclosed
- not recorded
- Independent of proponent
- not recorded
- Retracted
- No
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Published September 17, 2026.
Questions
How strong is the evidence behind this?
veisund rates this source "not yet assessed". We have not finished checking this source. No judgement either way. One caveat travels with that badge: NSDUH surveys the civilian, noninstitutionalized population aged 12 or older, so people in hospitals, prisons, nursing homes, on active duty or unsheltered are not in it; SAMHSA states that estimates from 2021 onward are not comparable with 2020 or earlier, so no line here runs back further than 2021. A survey answer is not a diagnosis. 'Any mental illness' and 'serious mental illness' are model estimates calibrated on clinical interviews, not counts of diagnoses. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Key Substance Use and Mental Health Indicators in the United States: Results from the 2025 National Survey on Drug Use and Health (full report PDF) — Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality (2026). The full source is linked on this page so you can read it yourself.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.