Every health policy decision depends on having an accurate estimate of how many people are living with a particular disorder. Yet for years the federal government has been erroneously measuring the number of people living with the most disabling mental illness – schizophrenia. Now a new study should change that – if the federal government pays attention.

This almost willful ignorance of severe mental illness is nothing new. Five years ago, a report by my organization, the Treatment Advocacy Center, pointed out that estimates of schizophrenia published on the website of the National Institute of Mental Health greatly understated the prevalence of the disease. Indeed, we showed that the NIMH had suddenly reduced — by a whopping 2 million people – its estimate for the number of people with schizophrenia, without any new data or research to back it up.

Among other gaps, the institute’s prevalence estimate relied on data that did not consider people in psychiatric hospitals, jails or prisons, as well as those who are homeless. It goes without saying that such results discount numerous people living with severe mental illness.

Following our report, the government acknowledged that there were problems with the data and, in 2019, SAMHSA – the Substance Abuse and Mental Health Services Administration – created the Mental Disorder Prevalence Study (MDPS) to address this glaring gap. After three years of data collection, results from that study were released this summer. 

Those results show that 1.8% of Americans aged 18-65 – 3.7 million people in all – have been diagnosed with schizophrenia spectrum disorders during their lifetime. That is 2 million more than NIMH currently reports

This is a huge deal. A 1.8% lifetime prevalence rate of schizophrenia spectrum disorders makes this mental illness more common than type 1 diabetes, multiple sclerosis, and ALS combined. 

Undercounting people with severe mental illness has devastating effects. It almost certainly contributes to the lack of treatment and other services for people living with the most severe of psychiatric disorders.

When people with schizophrenia don’t receive adequate treatment, the consequences can be deadly. The longer someone suffers from untreated psychosis, the more damage it can do to their brain, making it that much harder for them to return to their previous level of functioning.

A person with schizophrenia has twice the risk of dying by suicide compared to someone with other types of mental illness. And people with severe mental illness, especially if it’s untreated, frequently end up in our criminal legal system and are 16 times more likely to die in a law-enforcement encounter. 

The fact that there are two to three times more people with schizophrenia in the U.S. than previously measured means that we need two to three times more services than we currently have. Every local, state, and federal policy decision about mental health services should be based on an accurate understanding of how many people the system needs to serve.

To help correct the previous wrongs, policymakers should use the results from the new study to make new, informed decisions on funding allocations moving forward. 

Far too often, people with severe mental illness are left to live on the margins and in the shadows – including in research. To miscount them is to further discount them. Miscalculating the most basic information – the number of people experiencing a particular health condition – all but guarantees that they won’t receive the services they need. It’s not just irresponsible, it’s unconscionable and wrong.

The new results revealed by this study are a major step in the right direction. But it’s only a first step. We at the Treatment Advocacy Center will continue to work to ensure that we accurately measure the extent of severe mental illness and its impact on people, families and society. We implore the federal government to follow suit. 

Type of work:

Elizabeth Sinclair Hancq is a mental health policy researcher and public health professional currently serving as the director of research at Treatment Advocacy Center.