Misuse of Immediate-Release Stimulants: Response to Diller

To the Editor: We appreciate Dr. Diller’s thoughtful letter, which emphasizes clinical recommendations regarding stimulant prescribing, especially the importance of minimizing immediate-release stimulants that appear to be the most misused formulations. We provide some additional information to address this topic. The purpose of our recently published article was to simultaneously examine the prevalence and correlates of overall prescription stimulant use, misuse, use disorders, and motivations for misuse in the U.S. adult population (1). The 2015 and 2016 National Surveys on Drug Use and Health include immediate-release methylphenidate and amphetamine as well as multiple other formulations (Table 1). The full list of medications (along with pill images) are provided as a memory aid during the survey interview. However, analyzing specific formulations is not recommended because of potential recall bias and reporting errors by respondents who may not recognize the subtle labeling differences. Some researchers have reported that for adults with attention deficit hyperactivity disorder (ADHD), immediate-release methylphenidate is an effective treatment (2), and immediate-release amphetamine is as effective as sustained-release amphetamine (3). Researchers also have reported that among adults ages 18–49, the prevalence of nonmedical use is much higher for immediate-release than extended-release ADHD medications (4). We agree with Dr. Diller that the clinical indications for prescribing immediate-release stimulants for treating ADHD need to be better specified. Future research should examine the use, misuse, use disorders, and motivations for misuse of immediate-release methylphenidate and amphetamine among both youths and adults in the United States.