George R. Uhl, M.D., Ph.D., of the National Institutes of Health, Baltimore, Md., and Robert W. Grow, M.S., of the National Institutes of Health and The Johns Hopkins University School of Medicine, Baltimore, Md., provided estimates of the impact of complex genetics on brain and nervous system disorders (including depressive illness, stroke, Parkinson disease, Huntington disease, schizophrenia and anxiety disorders) in the United States based on approximations of disease costs to society and disease heritability. Costs were calculated based on literature sources and the Lewin-National Foundation for Brain Research estimates updated for population growth and consumer price index inflation. Heritability estimates were taken from studies based on twins.
"Brain and nervous system disorders may cost the United States as much as $1.2 trillion annually, and affect many millions of American each year," write the authors. "Twin data suggest that more than 40 percent of the societal burden of brain disorders is likely to be genetically mediated." The authors also suggest that most of the disease burden can be traced to complex, multi-gene interactions, as well as environmental factors. Less than 2 percent of the costs can be attributed to single-gene influences.
"The remarkable size of the burden that complex genetics of brain disorders places on the U.S. society implies that identifying the specific alleles [gene variations] of the genes that contribute to these disorders can have a large impact here and in the rest of the world," the researchers write. "Clinicians with interests in brain disorders should position themselves to aid the processes of identifying these alleles and to benefit from improved integration of these genetic insights with prevention, diagnosis, and treatment strategies for the many challenging disorders of the brain and nervous system."
(Arch Gen Psychiatry. 2004;61:223-229. Available post-embargo at archgenpsychiatry.com)
Editor's Note: This study was supported by the National Institute on Drug Abuse, Baltimore, Md.
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Journal
Archives of General Psychiatry