Neurobehavioral disorders, which include attention deficit hyperactivity disorder (ADHD), autism, and a variety of learning disabilities, affect 3-8% of U.S. children (Buxbaum, Boyle, Yeargin-Allsopp, Murphy, & Roberts, 2000; Kiely, 1987). Exposure to metals such as lead, mercury, and cadmium, as well as certain pesticides and organic solvents during pregnancy and childhood can impact normal brain development and function (Gilbert & Grant-Webster, 1995; Schettler, Stain, Reich, Valenti, & Wallinga, 2000).

Cost Estimates: Neurobehavioral disorders lead to costs for both medical treatment and special education.  Following the methodology of Landrigan et al., we calculate an estimate of the costs of neurobehavioral disorders in Oregon.

Landrigan et al. estimated the costs for three neurobehavioral disorders—mental retardation, autism, and cerebral palsy.  Their estimate uses yearly incidence data from the CDC (Buxbaum et al., 2000) and lifetime cost-per-case estimates based on cost estimates developed by Honeycutt, Dunlap, Chen and al Homsi (2000). This lifetime cost estimate of $92.0 billion in 1997$ incorporates both direct and indirect costs including hospitalizations, physician visits, prescription drugs, therapy and rehabilitation, home care, home and automobile modifications, special education services, and productivity losses due to morbidity.  The cost estimate does not include costs for social services and criminal justice, or lost wages and diminished productivity of parents who reduce work hours to care for their child. 

Because we later added in Oregon-specific costs for special education, we recalculated annualized national lifetime cost figures for cerebral palsy, mental retardation, and autism, omitting special education costs from the Landrigan et al. equation.  We used the 2000 annual per student costs for special education as reported in a study commissioned by the Oregon School Boards Association (Econorthwest, 2002). This per student cost of $671 in 2000 dollars is for all K-12 students enrolled in Oregon public schools, not just students in special education programs.  These costs cover classroom instruction and other special education services beyond the basic per pupil instructional costs. 

The per student cost was multiplied by the total number of students enrolled in Oregon K-12 public schools during the 2006-2007 school year to determine the total special education expenditures (Oregon Department of Education, 2007a).  This Oregon-specific cost estimate includes costs for the three disorders considered in the Landrigan et al. study, as well as other qualifying neurobehavioral and physical disorders.  Following Massey and Ackerman (2003), we reasoned that while special education includes services to children with physical disabilities distinct from neurobehavioral disorders, the fact that large numbers of children with true neurobehavioral disorders are not tested or offered special education counterbalances this potential over count.  

Environmentally-Attributable Factor Range (EAFR) and Best Estimate: In 2000, the National Academy of Sciences estimated that 3% of all neurobehavioral disorders in children are caused by direct exposure to environmental contaminants.  Additionally, this group of experts concluded that another 25% of neurobehavioral disorders are caused by interactions between broadly defined environmental factors and an individual’s genetic susceptibility (National Academy of Sciences Committee on Developmental Toxicology, 2000). 

Based on this information, Landrigan et al. (2002) used an EAFR of 5-20%. Similarly, Massey and Ackerman (2003) used EAFs of 5%, 10%, and 20%.  Following these examples, we use a best estimate of 10% and an EAFR of 5-20%. 

Costs in Oregon: We estimated the costs of the environmentally attributable portion of neurobehavioral disorders in Oregon by combining lifetime cost estimates determined by Landrigan et al. with Oregon-specific special education costs.  Our estimate of the costs of neurobehavioral disorders in Oregon attributable to environmental contaminants is based on the following assumptions:

• There were 562,828 K-12 Oregon public school children in the 2006-2007 school year;
• Oregon per student expenditures on special education were $671.00 in 2000 dollars; this is equivalent to $819.00 in 2007 dollars;
• Total national neurobehavioral costs of $120.5 billion in 2007 dollars;
• Landrigan’s estimate of total national neurobehavioral costs minus costs for special education = $88.5 billion in 1997 dollars or $115.9 billion in 2007 dollars;
• Oregon constitutes 1.22% of the U.S. population; and
• A best estimate of 10% and an EAFR of 5-20%.
  

Oregon annualized lifetime costs, minus special education:

[(Landrigan national estimate in 2007 dollars, minus special education) * (Oregon proportion of U.S. population)] = ($115.9 billion) * (0.0122) = $1.41 billion

Best estimate of 10% = $141.0 million

Range 5% to 20% = $70.5 million to $282.0 million

Oregon annual special education costs:

Actual Oregon special education expenditures for state FY 2006-2007 = ($819) * (562,828) = $460,956,132

Best estimate of 10% = $46.1 million

Range 5% to 20% = $23.0 – $92.2 million

Estimate of Oregon’s total annual costs of neurobehavioral disorders attributable to environmental causes:

(Oregon lifetime costs) + (Oregon special education costs) = Total Oregon costs

($141 million) + ($46.1 million) = $187.1 million (range $93.5-374.2 million)

• EAF 0.05 = $93.5 million
• EAF 0.10 = $187.1 million
• EAF 0.20 = $374.2 million
  

The costs of environmentally attributable neurobehavioral disorders in Oregon are estimated at $187.1 million per year, with a range of $93.5 to $374.2 million.

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