Researchers supported by the National Institute of Mental Health (NIMH) have found that half of all lifetime cases of mental illness begin by age 14, and that despite effective treatments, there are long delays — sometimes decades — between first onset of symptoms and when people seek and receive treatment. The study also reveals that an untreated mental disorder can lead to a more severe, more difficult to treat illness, and to the development of co-occurring mental illnesses.
The landmark study is described in four papers that document the prevalence and severity of specific mental disorders. The papers provide significant new data on the impairment — such as days lost from work — caused by specific disorders, including mood, anxiety, and substance abuse disorders. These measures will allow researchers to determine the degree of disability and the economic burden caused by mental illness, as well as trends over time.
The papers are reported in the June 6 issue of the Archives of General Psychiatry by Ronald Kessler, Ph.D., and colleagues. The study was a collaborative project between Harvard University, the University of Michigan, and the NIMH Intramural Research Program.
This study, called the National Comorbidity Survey Replication (NCS-R), is a household survey of 9,282 English-speaking respondents, age 18 and older. It is an expanded replication of the 1990 National Comorbidity Survey, which was the first to estimate the prevalence of mental disorders (using modern psychiatric standards) in a nationally representative sample. The expansion includes detailed measures that will significantly improve estimates of the severity and persistence of mental disorders, and the degree to which they impair individuals and families, and burden employers and the U.S. economy.
“These studies confirm a growing understanding about the nature of mental illness across the lifespan,” says Thomas Insel, M.D., Director of the National Institute of Mental Health. “There are many important messages from this study, but perhaps none as important as the recognition that mental disorders are the chronic disorders of young people in the U.S.”
Prevalence and Age-of-Onset of Mental Disorders
Unlike most disabling physical diseases, mental illness begins very early in life. Half of all lifetime cases begin by age 14; three quarters have begun by age 24. Thus, mental disorders are really the chronic diseases of the young. For example, anxiety disorders often begin in late childhood, mood disorders in late adolescence, and substance abuse in the early 20’s. Unlike heart disease or most cancers, young people with mental disorders suffer disability when they are in the prime of life, when they would normally be the most productive.
The risk of mental disorders is substantially lower among people who have matured out of the high-risk age range. Prevalence increases from the youngest group (age 18-29) to the next-oldest age group (age 30-44) and then declines, sometimes substantially, in the oldest group (age 60 +). Females have higher rates of mood and anxiety disorders. Males have higher rates of substance use disorders and impulse disorders.
The survey found that in the U.S., mental disorders are quite common; 26 percent of the general population reported that they had symptoms sufficient for diagnosing a mental disorder during the past 12 months. However, many of these cases are mild or will resolve without formal interventions.