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Prevalence of Generalized Anxiety Disorder

According to the National Comorbidity Survey Replication (NCSR), 5.7 percent of the general population in the United States has had generalized anxiety disorder during their lifetime. GAD is a painful and often debilitating disease with a risk of suicide, yet, according to the World Health Organization, as high as 57 percent of those suffering do not get treatment. Determining prevalence rates can tell us more about the condition and also raise questions about the current diagnosis.

  1. Identification

    • Generalized anxiety disorder involves excessive fear or worry with no specific focus. The Diagnostic and Statistical Manual, 4th Edition (DSM-IV) specifies generalized anxiety disorder as a condition characterized by excessive and uncontrollable worry lasting six months or more, with at least three (one for a child) of the following symptoms: muscle tension, sleep disturbance, difficulty concentrating, fatigue, irritability, feeling restless or wound-up.

    Types of Prevalence

    • In medical terms, "prevalence" refers to "proportion." Typically prevalence is reported as a 12-month prevalence (percentage of a population suffering from GAD in a given) or lifetime prevalence (proportion of a population who have had GAD at some point in their life). "Point prevalence" refers proportion diagnosed within a specified population or period.

    Measuring Prevalence

    • Whether one year, lifetime or some other measure, prevalence must be estimated with surveys. In the United States, the standard estimates were set in the National Comorbidity Survey (NCS) of 1990-1992, then the National Comorbidity Survey Replication (NCSR) of 2001-2002. These surveys used pioneering, tested and reliable, diagnostic questionnaires and interview tools that could be given by lay-persons to representative samples of the American population. Surveys of general practitioners or mental health professional may also be used to help assess the prevalence of disorders.

    Considerations

    • All surveys have some error. Error may come from interviewer mistakes, and from respondents who give false answers. There are ways to minimize the effects of this type of error with a large enough sample and various statistical tools.

    Controversy

    • Diagnosis in the DSM-IV for Generalized Anxiety Disorder requires that symptoms persist for six months. Recently, however, increasing evidence suggests those who suffer symptoms for less than six months may very well have an anxiety disorder. According to an article in the June 2005 edition of the New England Journal of Medicine, changing the 6 month requirements to one or three months could change lifetime prevalence rates to 7.5 percent and 5.2 percent respectively.

    Differing Rates

    • Rates may differ by region and country. The World Health Organization, for example reported the following rates: Berlin, 7.3, Paris 7.2, Mainz, 4.5; Manchester, 3.0; and Groningen, 1.5. Developing countries also show higher prevalence rates than undeveloped countries. At the same time, a low income and low education are risk factors. Women also consistently have higher rates than men no matter region or country.

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