The Epidemiology of Anxiety Disorders

Epidemiologic Data Sources

The most recent estimates of the prevalence of DSM-IV mental disorders in the United States come from the National Comorbidity Survey Replication (NCS-R).

Nationally representative household survey 9,282 respondents age 18 and older Face-to-face interviews between 2001 and 2003 Survey response rate: 70.9%

Source: Kessler RC, Wang PS. The descriptive epidemiology of commonly occurring mental disorders in the United States. Annual Rev Public Health 2008;29:115-129.

Measures

Lifetime prevalence: The proportion of a sample that has ever

experienced a given disorder at sometime in their life (up to their age at study)

12-month prevalence: The proportion of a sample that has experienced

a given disorder in the 12 months preceding the study

Age of onset

Lifetime Prevalence of Anxiety Disorders by Age

Total (%)

18-29 (%)

30-44 (%)

45-59 (%)

60+

Any anxiety disorder 28.8 30.2 35.1 30.8 15.3

Panic disorder 4.7 4.4 5.7 5.9 2.0

Agoraphobia (w/o panic) 1.4 1.1 1.7 1.6 1.0

Specific phobia 12.5 13.3 13.9 14.1 7.5

Social phobia 12.1 13.6 14.3 12.4 6.6

Generalized anxiety disorder

5.7 4.1 6.8 7.7 3.6

Post-traumatic stress disorder

6.8 6.3 8.2 9.2 2.5

Obsessive-compulsive disorder

1.6 2.0 2.3 1.3 0.7

Separation anxiety disorder 5.2 5.2 5.1 NA NA

Source: Kessler RC et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 62:593-602.

Lifetime Prevalence

Anxiety disorders are the most prevalent class of mental disorders

Lifetime prevalence is lowest in the oldest age group It is unclear whether this is due to methodological

factors… The exclusion of people living in institutions (e.g.,

nursing homes) from population surveys Those with anxiety disorders may have risk factors for

early mortality…or due to increasing risk among those born into

younger generations

Twelve-Month Prevalence of Anxiety Disorders by Severity

Total (%)

Serious (% of all cases)

Moderate (% of all cases)

Mild (% of all

cases)

Any anxiety disorder 18.1 22.8 33.7 43.5

Panic disorder 2.7 44.8 29.5 25.7

Agoraphobia (w/o panic) 0.8 40.6 30.7 28.7

Specific phobia 8.7 21.9 30.0 48.1

Social phobia 6.8 29.9 38.8 31.3

Generalized anxiety disorder

3.1 32.3 44.6 23.1

Post-traumatic stress disorder

3.5 36.6 33.1 30.2

Obsessive-compulsive disorder

1.0 50.6 34.8 14.6

Separation anxiety disorder

0.9 43.3 24.8 31.9

Source: Kessler RC et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 62:593-602.

Age of Onset (AOO)

The phobias and separation anxiety disorder (SAD) have very early AOO distributions

25th to 75th percentiles: 4 – 20 years

The other anxiety disorders have later AOO distributions

Source: Kessler RC, Wang PS. The descriptive epidemiology of commonly occurring mental disorders in the United States. Annual Rev Public Health 2008;29:115-129.

Limitations of Epidemiologic Data Sources

The NCS-R focused on household populations Exclusion of the homeless Exclusion of those living in institutions

Survey participation may be systematically higher in those who do not have mental disorders

Survey responses are based on retrospective recall

Possibility of recall errors or conscious nonreportingAs a result of these limitations, the prevalence

of anxiety disorders is likely underestimatedSource: Kessler RC, Wang PS. The descriptive epidemiology of commonly occurring mental disorders in the United States. Annual Rev Public Health 2008;29:115-129.

Sociodemographic Factors Associated with Anxiety Disorders

FemaleWhitesWidowed, divorced, or unmarriedUnemployment, having no occupationLow level of educationLow income

Sources: Michael T, Margraf J. Epidemiology of anxiety disorders. Psychiatry 2004;3(4):2-6.

National Institute of Mental Health Statistics.

Risk Factors for Anxiety Disorders

Behavioral inhibition during childhoodNegative life eventsFamily history of anxiety disorders (genetic

factors)

Sources: Michael T, Margraf J. Epidemiology of anxiety disorders. Psychiatry 2004;3(4):2-6.

Comorbid Conditions

The level of comorbidity among anxiety disorders is high

Anxiety disorders and affective disorders are strongly associated

Panic disorder and affective disorders GAD and affective disorders

Anxiety disorders and substance abuse disorders are associated, but not as strongly as comorbidity with affective disorders or other anxiety disorders

Sources: Michael T, Margraf J. Epidemiology of anxiety disorders. Psychiatry 2004;3(4):2-6.