Mental illnesses are common in the United States. It is estimated that more than one in five U.S. adults live with a mental illness (57.8 million in 2021). Mental illnesses include many different conditions that vary in degree of severity, ranging from mild to moderate to severe. Two broad categories can be used to describe these conditions: Any Mental Illness (AMI) and Serious Mental Illness (SMI). AMI encompasses all recognized mental illnesses. SMI is a smaller and more severe subset of AMI. Additional information on mental illnesses can be found on the NIMH Health Topics Pages.
The data presented here are from the 2021 National Survey on Drug Use and Health (NSDUH) by the Substance Abuse and Mental Health Services Administration (SAMHSA). For inclusion in NSDUH prevalence estimates, mental illnesses include those that are diagnosable currently or within the past year; of sufficient duration to meet diagnostic criteria specified within the 4th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV); and, exclude developmental and substance use disorders.
Any Mental Illness
- Any mental illness (AMI) is defined as a mental, behavioral, or emotional disorder. AMI can vary in impact, ranging from no impairment to mild, moderate, and even severe impairment (e.g., individuals with serious mental illness as defined below).
Serious Mental Illness
- Serious mental illness (SMI) is defined as a mental, behavioral, or emotional disorder resulting in serious functional impairment, which substantially interferes with or limits one or more major life activities. The burden of mental illnesses is particularly concentrated among those who experience disability due to SMI.
Prevalence of Any Mental Illness (AMI)
- Figure 1 shows the past year prevalence of AMI among U.S. adults.
- In 2021, there were an estimated 57.8 million adults aged 18 or older in the United States with AMI. This number represented 22.8% of all U.S. adults.
- The prevalence of AMI was higher among females (27.2%) than males (18.1%).
- Young adults aged 18-25 years had the highest prevalence of AMI (33.7%) compared to adults aged 26-49 years (28.1%) and aged 50 and older (15.0%).
- The prevalence of AMI was highest among the adults reporting two or more races (34.9%), followed by American Indian / Alaskan Native (AI/AN) adults (26.6%). The prevalence of AMI was lowest among Asian adults (16.4%).
|Race/Ethnicity||Hispanic or Latino*||20.7|
|Black or African American||21.4|
|2 or More||34.9|
*Persons of Hispanic origin may be of any race; all other racial/ethnic groups are non-Hispanic. NH/OPI = Native Hawaiian / Other Pacific Islander | AI/AN = American Indian / Alaskan Native
Mental Health Services — AMI
- Figure 2 presents data on mental health services (including virtual services) received within the past year by U.S. adults aged 18 or older with any mental illness (AMI). NSDUH defines mental health services as having received inpatient treatment/counseling or outpatient treatment/counseling, or having used prescription medication for problems with emotions, nerves, or mental health.
- In 2021, among the 57.8 million adults with AMI, 26.5 million (47.2%) received mental health services in the past year.
- More females with AMI (51.7%) received mental health services than males with AMI (40.0%).
- The percentage of young adults aged 18-25 years with AMI who received mental health services (44.6%) was lower than adults with AMI aged 26-49 years (48.1%) and aged 50 and older (47.4%).
|Race/Ethnicity||Hispanic or Latino*||36.1|
|Black or African American||39.4|
|Two or More Races||52.2|
*Persons of Hispanic origin may be of any race; all other racial/ethnic groups are non-Hispanic. Note: Estimates for Native Hawaiian / Other Pacific Islander and, American Indian / Alaskan Native groups are not reported in the above figure due to low precision of data collection in 2021.
Prevalence of Serious Mental Illness (SMI)
- Figure 3 shows the past year prevalence of SMI among U.S. adults.
- In 2021, there were an estimated 14.1 million adults aged 18 or older in the United States with SMI. This number represented 5.5% of all U.S. adults.
- The prevalence of SMI was higher among females (7.0%) than males (4.0%).
- Young adults aged 18-25 years had the highest prevalence of SMI (11.4%) compared to adults aged 26-49 years (7.1%) and aged 50 and older (2.5%).
- The prevalence of SMI was highest among AI/AN adults (9.3%), followed by adults reporting two or more races (8.2%). The prevalence of SMI was lowest among Asian adults (2.8%).
|Race/Ethnicity||Hispanic or Latino*||5.1|
|Black or African American||4.3|
|2 or More||8.2|
* Persons of Hispanic origin may be of any race; all other racial/ethnic groups are non-Hispanic. NH/OPI = Native Hawaiian / Other Pacific Islander | AI/AN = American Indian / Alaskan Native.
Mental Health Services — SMI
- Figure 4 presents data on mental health services received within the past year by U.S. adults 18 or older with serious mental illness (SMI). The NSDUH defines mental health services as having received inpatient treatment/counseling or outpatient treatment/counseling or having used prescription medication for problems with emotions, nerves, or mental health.
- In 2021, among the 14.1 million adults with SMI, 9.1 million (65.4%) received mental health treatment in the past year.
- More females with SMI (67.6%) received mental health treatment than males with SMI (61.3%).
- The percentage of young adults aged 18-25 years with SMI who received mental health treatment (57.9%) was lower than adults with SMI aged 26-49 years (67.0%) and aged 50 and older (71.0%).
|Race/Ethnicity||Hispanic or Latino*||58.6|
|Black or African American||62.3|
|Two or More Races||68.6|
*Persons of Hispanic origin may be of any race; all other racial/ethnic groups are non-Hispanic. Note: Estimates for Asian, Native Hawaiian / Other Pacific Islander, and American Indian / Alaskan Native groups are not reported in the above figure due to low precision.
Prevalence of Any Mental Disorder Among Adolescents
- Based on diagnostic interview data from National Comorbidity Survey Adolescent Supplement (NCS-A), Figure 5 shows lifetime prevalence of any mental disorder among U.S. adolescents aged 13-18.1
- An estimated 49.5% of adolescents had any mental disorder.
- Of adolescents with any mental disorder, an estimated 22.2% had severe impairment and/or distress. DSM-IV based criteria were used to determine severity level.
|With Severe Impairment||22.2|
- Merikangas KR, He JP, Burstein M, Swanson SA, Avenevoli S, Cui L, Benjet C, Georgiades K, Swendsen J. Lifetime prevalence of mental disorders in U.S. adolescents: results from the National Comorbidity Survey Replication--Adolescent Supplement (NCS-A). J Am Acad Child Adolesc Psychiatry. 2010 Oct;49(10):980-9. PMID: 20855043
- Substance Abuse and Mental Health Services Administration. (2022). Key substance use and mental health indicators in the United States: Results from the 2021 National Survey on Drug Use and Health (HHS Publication No. PEP22-07-01-005, NSDUH Series H-57). Rockville, MD: Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration. Retrieved from https://www.samhsa.gov/data/report/2021-nsduh-annual-national-report.
Statistical Methods and Measurement Caveats
National Survey on Drug Use and Health (NSDUH)
- The NSDUH AMI and SMI estimates were generated from a prediction model created from clinical interview data collected on a subset of adult NSDUH respondents who completed an adapted (past 12 month) version of the Structured Clinical Interview for DSM-IV-TR Axis I Disorders (Research Version, Non-patient Edition) (SCID-I/NP; First, Spitzer, Gibbon, & Williams, 2002), and was differentiated by level of functional impairment based on the Global Assessment of Functioning Scale (GAF; Endicott, Spitzer, Fleiss, & Cohen, 1976).
- The assessment included diagnostic modules assessing the following: mood, anxiety, eating, impulse control, substance use, adjustment disorders, and a psychotic symptoms screen.
- The assessment did not contain diagnostic modules assessing the following: adult attention deficit hyperactivity disorder (ADHD), autism spectrum disorders, schizophrenia or other psychotic disorders (although the assessment included a psychotic symptom screen).
- People who only have disorders that are not included in these diagnostic modules may not be adequately detected. However, there are known patterns of high comorbidities among mental disorders; these patterns increase the likelihood that people who meet AMI and/or SMI criteria were detected by the study, as they may also have one or more of the disorders assessed in the SCID-I/NP.
- The entirety of NSDUH respondents for the AMI and SMI estimates were the civilian, non-institutionalized population aged 18 years old or older residing within the United States.
- The survey covered residents of households (persons living in houses/townhouses, apartments, condominiums; civilians living in housing on military bases, etc.) and persons in non-institutional group quarters (e.g., shelters, rooming/boarding houses, college dormitories, migratory workers' camps, and halfway houses).
- The survey did not cover persons who, for the entire year, had no fixed address (e.g., homeless and/or transient persons not in shelters); were on active military duty; or who resided in institutional group quarters (e.g., correctional facilities, nursing homes, mental institutions, long-term hospitals).
- Some people in these excluded categories had AMI and/or SMI, but were not accounted for in the NSDUH AMI and/or SMI estimates.
- Data regarding sex of the respondent was assessed using male and female categories only. Gender identity information was not collected in the survey.
- In 2021, 53.0% of the selected NSDUH sample of people 18 or older did not complete the interview. This rate of non-response is higher than in previous years. Please see the Background on the 2021 NSDUH and the COVID-19 Pandemic section below for more information.
- Reasons for non-response to interviewing include the following: refusal to participate (30.1%); respondent unavailable or never at home (18.8%); and other reasons such as physical/mental incompetence or language barriers (4.2%).
- People with mental illness may disproportionately fall into these non-response categories. While NSDUH weighting includes non-response adjustments to reduce bias, these adjustments may not fully account for differential non-response by mental illness status.
- For some groups, data are not reported due to low precision. Data may be suppressed in the above charts if the data do not meet acceptable ranges for prevalence estimates, standard error estimates, and sample size.
Background on the 2021 NSDUH and the COVID-19 Pandemic:
- Data collection methods for the 2021 NSDUH changed in several ways because of the COVID-19 pandemic: the 2021 NSDUH continued the use of multimode data collection procedures (both in-person and virtual data collection) that were first implemented in the fourth quarter of the 2020 NSDUH. Overall, 54.6% of interviews were completed via the web, and 45.4% were completed in person. In 2021, the weighted response rates for household screening and for interviewing were 22.2% and 46.2%, respectively, for an overall response rate of 10.3% for people aged 12 or older.
- Given the use of multimode data collection procedures throughout the entirety of the collection year and the rate of non-response, comparison of estimates from the 2021 NSUDH with those from prior years must be made with caution.
Please see the 2021 National Survey on Drug Use and Health Methodological Summary and Definitions report for further information on how these data were collected and calculated.
National Comorbidity Survey Adolescent Supplement (NCS-A)
Diagnostic Assessment and Population:
- The NCS-A was carried out under a cooperative agreement sponsored by NIMH to meet a request from Congress to provide national data on the prevalence and correlates of mental disorders among U.S. youth. The NCS-A was a nationally representative, face-to-face survey of 10,123 adolescents aged 13 to 18 years in the continental United States. The survey was based on a dual-frame design that included 904 adolescent residents of the households that participated in the adult U.S. National Comorbidity Survey Replication and 9,244 adolescent students selected from a nationally representative sample of 320 schools. The survey was fielded between February 2001 and January 2004. DSM-IV mental disorders were assessed using a modified version of the fully structured World Health Organization Composite International Diagnostic Interview.
- The overall adolescent non-response rate was 24.4%. This is made up of non-response rates of 14.1% in the household sample, 18.2% in the un-blinded school sample, and 77.7% in the blinded school sample. Non-response was largely due to refusal (21.3%), which in the household and un-blinded school samples came largely from parents rather than adolescents (72.3% and 81.0%, respectively). The refusals in the blinded school sample, in comparison, came almost entirely (98.1%) from parents failing to return the signed consent postcard.
For more information, see PMID: 19507169 and the NIMH NCS-A study page.
Last Updated: March 2023