RESEARCH WEEKLY: More people with schizophrenia in the U.S. than previously reported

By Elizabeth Sinclair Hancq

(June 28, 2023) Groundbreaking new data released this week suggests there are 3.7 million adults living with schizophrenia spectrum disorders, including schizophrenia, schizoaffective disorder, and schizophreniform disorder. These results suggest that the number of individuals with schizophrenia spectrum disorders is two to three times higher than previously reported.  

The new data is from the Mental and Substance Use Disorders Prevalence Study, a national epidemiological survey that was conducted by RTI International and created and funded in 2019 by the Substance Abuse and Mental Health Services Administration. MDPS is unique, because trained clinicians conducted interviews with not only people living in households, but also individuals housed in prisons, state psychiatric hospitals, and homeless shelters, who had not been taken into account in previous estimates. The broader scope of those interviewed reflects much more accurate estimates of the prevalence of severe mental illness in the United States. Additionally, the incorporation of clinical interviews in the study design allows for more precise counts of people living with severe mental illnesses. 

The study was created by SAMHSA’s Assistant Secretary for Mental Health and Substance Use from 2017-2021 Dr. Elinore McCance-Katz to address major knowledge gaps in our understanding of the number of people living with serious mental illness in the United States. This was in response to a report published by Dr. E. Fuller Torrey and me in “Psychiatric Times” calling attention to the major shortcomings of current prevalence estimates and the National Institute of Mental Health changing their prevalence estimate of schizophrenia, despite no new data being published. The attention that Treatment Advocacy Center’s report received provided the support needed to get the notice of policymakers to address the miscounting of severe mental illness in the U.S. and directly resulted in the creation of the MDPS project. 

MDPS is a cooperative agreement between RTI International and SAMHSA in collaboration with Columbia University/New York State Psychiatric Institute, Duke Health, University of Washington, Harvard University, University of Chicago, and Treatment Advocacy Center.  

A deeper dive into the schizophrenia results 

MDPS found that 1.8% of adults aged 18-65 in the United States have a lifetime diagnosis of a schizophrenia spectrum disorder. Approximately two-thirds of those individuals, or 1.2% of the adult population, have a past-year diagnosis of schizophrenia spectrum disorder, meaning they experienced psychosis symptoms in the 12 months prior to being interviewed for the study.  

This translates to 3.7 million individuals with schizophrenia spectrum disorders living in the United States, 2.4 million of whom had active symptoms in the past year. This means there are two million more individuals living with a schizophrenia spectrum disorder in the United States than what is currently listed on the NIMH website.  

MDPS also asked participants about their treatment history in the past year. Of those with schizophrenia spectrum disorder, 73% received some type of treatment in the previous 12 months, according to the results. For those with schizophrenia spectrum disorder: 

• 66% received some outpatient treatment. 
• 12% received some psychiatric inpatient treatment.  
• 69% received some type of psychotropic medication. 

However, it is important to note that these treatment rates do not represent adequate treatment. In order to be categorized as receiving any treatment, an individual needs to have received some type of mental health treatment with at least one outpatient or inpatient visit and any type of psychotropic medication, not necessarily treatment specific for schizophrenia or psychosis. Therefore, the prevalence of having received meaningful treatment for their disorder is likely much lower than this.  

Policy implications



The results from this study have several important policy implications. First, the results indicate that sensitive, ethical, and rigorous research methods can be implemented to ensure that people with serious mental illness are more accurately measured in epidemiological research, including those living in non-household settings. Second, the results show there are significantly more treatment and other social services needed for the almost two million more people living with schizophrenia in the United States than previously measured. Severe mental illnesses like schizophrenia often require intensive treatment that depends on local, state, and federal resources to fund and provide the services. Policy leaders should utilize this new data to understand their community needs and allocate resources appropriately.  

The implications of the mistakes of the past are profound – underestimating the number of people with severe mental illness almost certainly contributes to the lack of adequate treatment and other services for these individuals with the most severe of psychiatric disorders. While the MDPS results are a major step in the right direction for the prioritization of people with severe mental illness, it took the attention garnered by Treatment Advocacy Center’s spotlight on the miscounting to get us there. We will continue to work to ensure there are continued efforts to accurately measure how severe mental illness impacts people, families, and society.  

Each year, we honor our founder, Dr. E. Fuller Torrey, through the Torrey Action Fund. The Torrey Action Fund is an annual fundraising campaign that supports everything we do, including critical research into severe mental illness and the publication of Research Weekly. Please consider donating to the Torrey Action Fund and help us continue our important work. TreatmentAdvocacyCenter.org/Donate 

Elizabeth Sinclair Hancq is the director of research at Treatment Advocacy Center.

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