Background: The diversion of prescription stimulants for misuse, particularly those used in the treatment of attention-deficit hyperactivity disorder (ADHD), is potentially a significant problem for public health and for healthcare funding and delivery. Most prior research on the diversion of prescription stimulants for misuse, particularly those used in the treatment of ADHD, has focused on the 'end users' of diverted medications rather than the suppliers. Furthermore, little is known about the direct costs of diversion for third-party insurance payers in the US. Objectives: The objectives of this study were to estimate the prevalence in the US of people whose private insurance paid costs for ADHD prescriptions that they gave or sold to another person (diversion), and to estimate medication costs of diversion to private insurers. Methods: Estimates are from a cross-sectional survey of respondents from two Internet survey panels targeting individuals aged 18-49 years in the civilian, noninstitutionalized US population, principally for those who filled prescriptions for ADHD medications in the past 30 days that were covered by private health insurance. Analysis weights were post-stratified to control totals from the Current Population Survey and National Health Interview Survey. Weighted prevalence rates and standard errors for diversion are reported, as are the costs of diverted pills using drug prices reported in the 2008 Thomson Reuters RED BOOK. Sensitivity analyses were conducted that varied the cost assumptions for medications. Results: Among individuals aged 18-49 years whose private insurance paid some costs for ADHD medications in the past 30 days, 16.6% diverted medications from these prescriptions. Men aged 18-49 years for whom private insurance paid some costs of ADHD drugs in the past 30 days were more than twice as likely as their female counterparts to divert medications from these prescriptions (22.5% vs 9.1%; p = 0.03). After a pro-rated co-payment share was subtracted, the estimated value of diverted medications in a 30-day period was $US8.0 million. Lower- and upper-bound estimates were $US6.9 million to $US17 million, for a range of $US83 million to $US204 million annually. Overall, diversion accounted for about 3.6% of the total costs that private insurers paid for ADHD medications (range: 3.5-4.5%). The percentages varied by medication category, although relative differences were sensitive to inclusion of a pro-rated co-payment. A higher percentage of the costs of extended-release (XR) medications was lost to diversion compared with that for immediate-release (IR) medications. Conclusions: Costs of ADHD medications paid for by private insurers that were lost to diversion were small relative to the total estimated medication costs and relative to total estimated healthcare costs for treating ADHD. Nevertheless, there may be significant cost savings for insurers if diversion can be reduced, particularly for XR medications. These findings represent a first step to informing policies to reduce diversion both in the interest of public health and for direct and indirect cost savings to insurers
