, according to the first study to estimate the national prevalence of schizophrenia spectrum disorders.
This finding is “especially important,” given that people with schizophrenia spectrum disorders experience “high levels of disability that present significant challenges in all aspects of their life,” principal investigator Heather Ringeisen, PhD, with RTI International, a nonprofit research institute based on Research Triangle Park, N.C., said in a statement.
The results “highlight the need to improve systems of care and access to treatment for people with schizophrenia and other mental health disorders,” added co–principal investigator Mark J. Edlund, MD, PhD, also with RTI.
The study also found that prevalence rates of many other nonpsychotic disorders were generally within an expected range in light of findings from prior research – with three exceptions.
Rates of major depressive disorder (MDD), generalized anxiety disorder (GAD), and obsessive-compulsive disorder (OCD) were higher than reported in past nationally representative samples.
The new data come from the Mental and Substance Use Disorder Prevalence Study (MDPS), a pilot program funded by the Substance Abuse and Mental Health Services Administration (SAMHSA).
A nationally representative sample of 5,679 adults aged 18-65 residing in U.S. households, prisons, homeless shelters, and state psychiatric hospitals were interviewed, virtually or in person, between October 2020 and October 2022.
The research team used a population-based version of the Structured Clinical Interview of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; SCID-5) for mental health and substance use disorder diagnostic assessment.
Among the key findings in the report:
- Nearly 2% of adults (about 3.7 million) had a lifetime history of schizophrenia spectrum disorders, which include schizophrenia, schizoaffective disorder, and schizophreniform disorder.
- Roughly 2.5 million adults (1.2%) met diagnostic criteria for a schizophrenia spectrum disorder in the past year.
- The two most common mental disorders among adults were MDD (15.5%, or about 31.4 million) and GAD (10.0%, or about 20.2 million).
- Approximately 8.2 million adults (4.1%) had past-year posttraumatic stress disorder, about 5.0 million (2.5%) had OCD, and roughly 3.1 million (1.5%) had bipolar I disorder.
- Alcohol use disorder (AUD) was the most common substance use disorder among adults aged 18-65; roughly 13.4 million adults (6.7%) met criteria for AUD in the past year.
- About 7.7 million adults (3.8%) had cannabis use disorder, about 3.2 million (1.6%) had stimulant use disorder, and about 1 million (0.5%) had opioid use disorder.
Multiple comorbidities
The data also show that one in four adults had at least one mental health disorder in the past year, most commonly MDD and GAD.
About 11% of adults met the criteria for at least one substance use disorder, with AUD and cannabis use disorder the most common.
In addition, an estimated 11 million adults aged 18-65 had both a mental health disorder and a substance use disorder in the past year.
Encouragingly, the findings suggest that more individuals are seeking and accessing treatment compared with previous studies, the authors noted; 61% of adults with a mental health disorder reported having at least one visit with a treatment provider in the past year.
However, considerable treatment gaps still exist for the most common mental health disorders, they reported. Within the past year, more than 40% of adults with MDD and more than 30% of those with GAD did not receive any treatment services.
The full report is available online.
A version of this article originally appeared on Medscape.com.