Q. Do you know of a recent book or article that states the top three mental illnesses for adults, elderly and children in specified counties or states?

A. I am not aware of any national studies that break down U.S. mental illness prevalence figures by state or age group. The closest I can get you is the Epidemiologic Catchment Area (ECA) study (see Regier et al, Archives of General Psychiatry 1984;41:934-41), which studied those age 18 or older, in five urban sites in the U.S.

At that time, the lifetime prevalence of the major mental disorders in the US were as follows: substance use disorders (alcohol & drug abuse/dependence) 16.4%; anxiety disorders 14.6%; Affective (mood) disorders 8.3%; and schizophrenia 1.5%. Lifetime prevalence means the number of people who acquire the illness at anytime over the course of their lifetime. Extrapolating from these percentages, and based on the 1999 US census of about 273 million people, we can calculate that about 44 million Americans suffer from substance use disorders at some time in their lives; 40 million from anxiety disorders (mainly phobic conditions); 23 million from mood disorders; and 4 million from schizophrenia.

Obviously, these are only approximate extrapolations from the ECA study, which was based on five representative urban sites in the US. Furthermore, if we expand our diagnostic criteria for bipolar disorder to include so-called bipolar spectrum disorders, the numbers undoubtedly rise. In children, the break-down by disease category may differ.

For example, a recent study of parent-reported disabling mental health conditions among U.S. children (Halfon & Newacheck, J Am Acad Child Adolesc Psychiatry 1999 May;38(5):600-9; discussion 610-3) found that the most common reported causes of disability include mental retardation, attention-deficit hyperactivity disorder, and learning disabilities. Such parent-based surveys are not necessarily going to reveal actual prevalence rates, as determined by clinical interview, but they are at least suggestive.

January 2003

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