Mental disorders are common in the United States and internationally. An estimated 26.2 percent of Americans ages 18 and older or about one in four adults suffer from a diagnosable mental disorder in a given year. When applied to the 2004 U.S. Census residential population estimate for ages 18 and older, this figure translates to 57.7 million people.
Even though mental disorders are widespread in the population, the main burden of illness is concentrated in a much smaller proportion about 6 percent, or 1 in 17 who suffer from a serious mental illness. In addition, mental disorders are the leading cause of disability in the U.S. and Canada for ages 15-44. Many people suffer from more than one mental disorder at a given time. Nearly half (45 percent) of those with any mental disorder meet criteria for two or more disorders, with severity strongly related to comorbidity.
In the U.S., mental disorders are diagnosed based on the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).
Mood disorders include major depressive disorder, dysthymic disorder, and bipolar disorder.
- Approximately 20.9 million American adults, or about 9.5 percent of the U.S. population age 18 and older in a given year, have a mood disorder.
- The median age of onset for mood disorders is 30 years.
- Depressive disorders often co-occur with anxiety disorders and substance abuse.
- In 2004, 32,439 (approximately 11 per 100,000) people died by suicide in the U.S.7
- More than 90 percent of people who kill themselves have a diagnosable mental disorder, most commonly a depressive disorder or a substance abuse disorder.
- The highest suicide rates in the U.S. are found in white men over age 85.
- Four times as many men as women die by suicide; however, women attempt suicide two to three times as often as men.
- Approximately 2.4 million American adults, or about 1.1 percent of the population age 18 and older in a given year, have schizophrenia.
- Schizophrenia affects men and women with equal frequency.
- Schizophrenia often first appears in men in their late teens or early twenties. In contrast, women are generally affected in their twenties or early thirties.
Anxiety disorders include panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, generalized anxiety disorder, and phobias (social phobia, agoraphobia, and specific phobia).
- Approximately 40 million American adults ages 18 and older, or about 18.1 percent of people in this age group in a given year, have an anxiety disorder.
- Anxiety disorders frequently co-occur with depressive disorders or substance abuse.
- Most people with one anxiety disorder also have another anxiety disorder. Nearly three-quarters of those with an anxiety disorder will have their first episode by age 21.5.
- Approximately 6 million American adults ages 18 and older, or about 2.7 percent of people in this age group in a given year, have panic disorder.
- Panic disorder typically develops in early adulthood (median age of onset is 24), but the age of onset extends throughout adulthood.
- About one in three people with panic disorder develops agoraphobia, a condition in which the individual becomes afraid of being in any place or situation where escape might be difficult or help unavailable in the event of a panic attack.
Obsessive-Compulsive Disorder (OCD)
- Approximately 2.2 million American adults age 18 and older, or about 1.0 percent of people in this age group in a given year, have OCD.
- The first symptoms of OCD often begin during childhood or adolescence, however, the median age of onset is 19.
Post-Traumatic Stress Disorder (PTSD)
- Approximately 7.7 million American adults age 18 and older, or about 3.5 percent of people in this age group in a given year, have PTSD.
- PTSD can develop at any age, including childhood, but research shows that the median age of onset is 23 years.
- About 19 percent of Vietnam veterans experienced PTSD at some point after the war. The disorder also frequently occurs after violent personal assaults such as rape, mugging, or domestic violence; terrorism; natural or human-caused disasters; and accidents.
Generalized Anxiety Disorder (GAD)
- Approximately 6.8 million American adults, or about 3.1 percent of people age 18 and over, have GAD in a given year.
- GAD can begin across the life cycle, though the median age of onset is 31 years old.
- Approximately 15 million American adults age 18 and over, or about 6.8 percent of people in this age group in a given year, have social phobia.
- Social phobia begins in childhood or adolescence, typically around 13 years of age.
The three main types of eating disorders are anorexia nervosa, bulimia nervosa, and binge-eating disorder.
- Females are much more likely than males to develop an eating disorder. Only an estimated 5 to 15 percent of people with anorexia or bulimia and an estimated 35 percent of those with binge-eating disorder are male.
- In their lifetime, an estimated 0.5 percent to 3.7 percent of females suffer from anorexia, and an estimated 1.1 percent to 4.2 percent suffer from bulimia.
- Community surveys have estimated that between 2 percent and 5 percent of Americans experience binge-eating disorder in a 6-month period.
- The mortality rate among people with anorexia has been estimated at 0.56 percent per year, or approximately 5.6 percent per decade, which is about 12 times higher than the annual death rate due to all causes of death among females ages 15-24 in the general population.
Attention Deficit Hyperactivity Disorder (ADHD)
- ADHD, one of the most common mental disorders in children and adolescents, also affects an estimated 4.1 percent of adults, ages 18-44, in a given year.
- ADHD usually becomes evident in preschool or early elementary years. The median age of onset of ADHD is seven years, although the disorder can persist into adolescence and occasionally into adulthood.
Autism is part of a group of disorders called autism spectrum disorders (ASDs), also known as pervasive developmental disorders. ASDs range in severity, with autism being the most debilitating form while other disorders, such as Asperger syndrome, produce milder symptoms.
- Estimating the prevalence of autism is difficult and controversial due to differences in the ways that cases are identified and defined, differences in study methods, and changes in diagnostic criteria. A recent study reported the prevalence of autism in 3-10 year-olds to be about 3.4 cases per 1000 children.
- Autism and other ASDs develop in childhood and generally are diagnosed by age three.
- Autism is about four times more common in boys than girls. Girls with the disorder, however, tend to have more severe symptoms and greater cognitive impairment.
- AD affects an estimated 4.5 million Americans. The number of Americans with AD has more than doubled since 1980.
- AD is the most common cause of dementia among people age 65 and older.
- Increasing age is the greatest risk factor for Alzheimer’s. In most people with AD, symptoms first appear after age 65. One in 10 individuals over 65 and nearly half of those over 85 are affected. Rare, inherited forms of Alzheimer’s disease can strike individuals as early as their 30s and 40s.
- From the time of diagnosis, people with AD survive about half as long as those of similar age without dementia.
Source: National Institute of Mental Health (NIMH)