While many people think that mental illnesses are rare; actually, there are many common mental disorders. In fact, according to the National Institute of Mental Health (NIMH), almost one-in-five people have a mental disorder diagnosable now or in the past year (not including those with substance related disorders). In 2013, this number represented 43.8 million adults in the United States with some kind of mental disorder, showing just how common mental disorders are (List of Mental Illnesses).
Most Common Mental Disorder: Anxiety Disorders
Anxiety disorders are the most common mental disorder in the United States. According to the NIMH, 18.1% of adults had some form of anxiety disorder within the year and 4.1% of people have an anxiety disorder that would be classified as "severe." The average age of onset of an anxiety disorder is 11 years old (Anxiety and Children: Symptoms, Causes of Childhood Anxiety).
Anxiety disorders is a group of disorders that include (but is not limited to) the following:
- Specific phobias exist in 8.7% of adults with 1.9% of adults being classified as having a "severe" specific phobia (Types of Phobias: Social Phobias and Specific Phobias).
- Social phobia exists in 6.8% of adults with 2% of adults being classified as having "severe" social phobia.
- Posttraumatic stress disorder exists in 3.5% of adults with 1.3% of adults being classified as having "severe" posttraumatic stress disorder.
- Generalized anxiety disorder exists in 3.1% of adults with 1% of adults being classified as having "severe" generalized anxiety disorder.
- Panic disorder exists in 2.7% of adults with 1.2% of adults being classified as having "severe" panic disorder.
It's worth noting that this common type of mental health disorder is also very frequently reported in children. Youths age 13-18 have a 25.1% lifetime prevalence of an anxiety disorder.
Common Mental Health Disorders: Mood Disorders
Mood disorders are the second most common type of mental disorder. According to the NIMH, the 12-month prevalence of any mood disorder for adults in the United States is 9.5% and 4.3% of adults with mood disorders would be classified as "severe" cases. Women are 50% more likely than men to experience a mood disorder over the course of their lifetime.
Mood disorders include the following:
- Major depression has a 12-month prevalence in adults of 6.7% (Major Depression [MDD] Symptoms, Causes, Treatments).
- Bipolar disorder is experienced by 2.6% of the adult population and 2.2% of people have a case that is considered "severe" bipolar disorder.
- Dysthymic disorder (a low-grade depression for more than two years) is experienced by 1.5% of the adult population with 0.8% of people have a case of dysthymic disorder considered "severe."
Common Mental Health Disorders: Personality Disorders
The third most common type of mental disorder is a personality disorder with 9.1% of adults experiencing a personality disorder in a given year. In this case, personality disorders included in that figure are antisocial personality disorder, avoidant personality disorder and borderline personality disorder.
The most common personality disorder is avoidant personality disorder which is experienced by 5.2% of adults in the United States in any given year. This common mental disorder is characterized by extreme social inhibition (shyness), feelings of inadequacy and acute sensitivity to actual or perceived rejection to the level where the person avoids social interaction and is impacted negatively day-to-day.