What is the incidence of mental illness in adults in the United States?

Incidence of Mental Illness in US Adults

According to the most recent data, approximately 25% of adults in the United States reported having a mental illness in the previous year, representing a substantial public health burden with significant impacts on morbidity, mortality, and quality of life. 1

Overall Prevalence Statistics

• The 2013 National Survey on Drug Use and Health revealed that an estimated 10 million adults (4.2% of the adult population) met the criteria for Serious Mental Illness (SMI) 2
• SMI is defined as a "diagnosable mental, behavioral, or emotional disorder that has resulted in serious functional impairment, which substantially interferes with or limits one or more major life activities" 2
• Common diagnoses associated with SMI include schizophrenia, major depression, and bipolar disorder 2
• More recent data from 2019 indicates that 61.2 million adults in the United States had a mental health disorder in the past year 3

Specific Mental Health Conditions and Co-occurring Disorders

• Among adults with serious mental illness, 35% have a history of homelessness or incarceration 4
• Substance use disorders remain prevalent, with an estimated 21.6 million persons aged 12 years or older (8.2% of the population) classified with substance dependence or abuse in 2013 2
• Co-occurring substance use and mental health disorders affected 7.7 million adults (3.2% of the adult population) in 2013 2
• Depression data from 2005-2008 indicated that 6.8% of adults had moderate to severe depression in a two-week period 1
• The prevalence of depression showed geographic variation, with higher rates generally observed in southeastern states 1

Treatment Patterns and Gaps

• Only 40% of individuals with serious mental illness received treatment in a 12-month period 5
• Of those receiving treatment, only 38.9% received care that could be considered at least minimally adequate 5
• This means only approximately 15.3% of all individuals with serious mental illness received minimally adequate treatment 5
• Fewer than two-thirds of adults with serious mental illness had seen a mental health professional in the past year 4
• During 2007-2008, approximately 5% of ambulatory care visits involved patients with a diagnosis of a mental health disorder, primarily depression, psychoses, or anxiety disorders 1

Risk Factors and Vulnerable Populations

• Adult women are more likely to be diagnosed with mental illness than men 2
• Predictors of inadequate treatment include being a young adult, being African American, residing in the South, having a psychotic disorder, and being treated in the general medical sector 5
• Individuals with SMI have higher rates of shortened life spans, substance abuse issues, and physical comorbidities compared to the general population 2
• Social issues such as homelessness and unemployment are disproportionately found in populations with serious mental illness 2

Economic and Healthcare System Impact

• The economic cost of mental illness in the United States is substantial, estimated at approximately $300 billion in 2002 1
• There is a substantial shortage in the availability of psychiatric inpatient beds, leading to "boarding" of patients in emergency departments and inappropriate placement in the prison system 2
• Mental illnesses account for a larger proportion of disability in developed countries than any other group of illnesses, including cancer and heart disease 1

These statistics highlight the critical need for improved access to mental health services, enhanced quality of care, and targeted interventions for vulnerable populations to address the significant burden of mental illness in the United States.