According to SAMHSA’s 2014 National Survey on Drug Use and Health (NSDUH) (PDF | 3.4 MB) an estimated 43.6 million (18.1%) Americans ages 18 and up experienced some form of mental illness. In the past year, 20.2 million adults (8.4%) had a substance use disorder. Of these, 7.9 million people had both a mental disorder and substance use disorder, also known as co-occurring mental and substance use disorders.
Various mental and substance use disorders have prevalence rates that differ by gender, age, race, and ethnicity. To read more about this, visit the Specific Populations and Health Disparities topics, and to find SAMHSA data that can be sorted on various factors, visit the NSDUH page.
Mental disorders involve changes in thinking, mood, and/or behavior. These disorders can affect how we relate to others and make choices. Mental disorders take many different forms, with some rooted in deep levels of anxiety, extreme changes in mood, or reduced ability to focus or behave appropriately. Others involve unwanted, intrusive thoughts and some may result in auditory and visual hallucinations or false beliefs about basic aspects of reality. Reaching a level that can be formally diagnosed often depends on a reduction in a person’s ability to function as a result of the disorder.
Anxiety disorders are the most common type of mental disorders, followed by depressive disorders. Different mental disorders are more likely to begin and occur at different stages in life and are thus more prevalent in certain age groups. Lifetime anxiety disorders generally have the earliest age of first onset, most commonly around age 6. Other disorders emerge in childhood, approximately 11% of children 4 to 17 years of age (6.4 million) have been diagnosed with attention deficit hyperactivity disorder (ADHD) as of 2011. Schizophrenia spectrum and psychotic disorders emerge later in life, usually in early adulthood. Not all mental health issues first experienced during childhood or adolescence continue into adulthood, and not all mental health issues are first experienced before adulthood. Mental disorders can occur once, reoccur intermittently, or be more chronic in nature. Mental disorders frequently co-occur with each other and with substance use disorders. Because of this and because of variation in symptoms even within one type of disorder, individual situations and symptoms are extremely varied.
Serious Mental Illness
Serious mental illness among people ages 18 and older is defined at the federal level as having, at any time during the past year, a diagnosable mental, behavior, or emotional disorder that causes serious functional impairment that substantially interferes with or limits one or more major life activities. Serious mental illnesses include major depression, schizophrenia, and bipolar disorder, and other mental disorders that cause serious impairment. In 2014, there were an estimated 9.8 million adults (4.1%) ages 18 and up with a serious mental illness in the past year. People with serious mental illness are more likely to be unemployed, arrested, and/or face inadequate housing compared to those without mental illness.
Substance Use Disorders
Substance use disorders occur when the recurrent use of alcohol and/or drugs causes clinically significant impairment, including health problems, disability, and failure to meet major responsibilities at work, school, or home.
In 2014, about 21.5 million Americans ages 12 and older (8.1%) were classified with a substance use disorder in the past year. Of those, 2.6 million had problems with both alcohol and drugs, 4.5 million had problems with drugs but not alcohol, and 14.4 million had problems with alcohol only.