Trends in Stimulant Medication Use in Commercially Insured Youths and Adults, 2010-2014

Stimulants are the most commonly prescribed treatment of attention-deficit/hyperactivity disorder (ADHD) in youths, and according to a nationally representative US household survey, there has been a sizeable increase in stimulant use among youth, from 4.0% between 1996 and 1998 to 6.6% between 2010 and 2012.¹ Also, during the last decade, the US Food and Drug Administration approved an indication for stimulant use in adults to treat ADHD.

Studies of office-based physician visits by adults showed that the proportion of visits with a prescribed stimulant grew 7-fold, from 0.1% between 1994 and 1997 to 0.7% between 2006 and 2009,² and the percentage of visits with ADHD diagnosis doubled from 0.3% between 1999 and 2002 to 0.7% between 2007 and 2010.³ Also, compared with youth ADHD visits, adult ADHD visits comprised a distinctly larger proportion of female and commercially insured visits.³ However, little is known about the trends in stimulant use within the past few years, specifically within commercially insured US populations. This study uses data from a large, commercially insured population to characterize recent trends and patterns of stimulant use according to age and sex.

A repeated cross-sectional design was applied to 5 years (2010-2014) of administrative claims data on youths (0-19 years) and adults (20-64 years) who were continuously enrolled (>90% of total enrollees) in a Blue Cross Blue Shield health insurance plan annually in Illinois, New Mexico, Oklahoma, or Texas (>3.5 million persons/year). We assessed stimulant use (persons with ≥1 methylphenidate and amphetamine-related product dispensings) expressed as percentage of continuous enrollees in each year according to sex and age group. With multivariable logistic regression models, we assessed the odds of stimulant use in 2014 vs 2010, adjusting for sociodemographic factors. We also examined clinician-reported ADHD diagnosis (International Classification of Diseases, Ninth Revision, Clinical Modification code 314.xx) in stimulant-treated youth and adults. The study used deidentified data and the University of Maryland Institutional Review Board did not require approval.

From 2010 to 2014, the prevalence of stimulant use increased across all age groups, although it was markedly greater among adults (P < .001) (Table). Stimulant use increased from 2.7% to 3.1% in 0- to 9-year-olds (adjusted odds ratio [AOR], 1.16; 95% CI, 1.13-1.18); from 6.2% to 7.2% in 10- to 19-year-olds (AOR, 1.27; 95% CI, 1.25-1.29); from 2.2% to 3.6% in 20- to 39-year-olds (AOR, 1.84; 95% CI, 1.81-1.87); and from 1.0% to 1.5% in 40- to 64-year-olds (AOR, 1.66; 95% CI, 1.63-1.69) (Table). Slight but statistically significant differences were observed in growth of stimulant use by sex among 10- to 19-year-olds and 20- to 39-year-olds (Table).

In 2014, stimulant prevalence was substantially greater in boys than girls from ages 0 to 19 years (7.1% vs 3.5%; P < .001), but it did not differ by sex from ages 20 to 34 years (4.0% vs 4.0%; P = .95) (Figure). In contrast, stimulant use was greater in women than men from ages 35 to 64 years (1.9% vs 1.3%; P < .001) (Figure).

In 2014, as a percentage of total stimulant dispensings, amphetamine-related products predominated in adults (83.6% [488 322/583 885]), whereas methylphenidate was more common in youth (52.5% [247 710/472 248]) (data not shown). Among those treated with stimulants, a clinician-reported ADHD diagnosis was more common among youths than adults (62.0% [40 055/64 626] vs 45.5% [33 790/74 269]) (data not shown).

In a commercially insured population, in just 5 years, between 2010 and 2014, the proportion of adults treated with stimulants grew rapidly in contrast to youths, who had a modest increase in stimulant use. The increase in adult stimulant use may be largely driven by increases in outpatient diagnoses of adult ADHD.³ However, consistent with previous reports,⁴ we show that a large proportion of stimulant-treated adults lacked an ADHD diagnosis, potentially reflecting off-label use. This raises concerns regarding potential nonmedical use of prescription stimulants.^5,6

The study limitations include dispensings that may not represent actual consumption and limited data on clinical appropriateness of treatment. Finally, the findings may not be nationally representative. Nevertheless, our study reports a prominent expansion in stimulant use among adults in a large, commercially insured population and supports further research to better understand outcomes of stimulant use, particularly among adult women.

Corresponding Author: Julie M. Zito, PhD, Departments of Pharmaceutical Health Services Research and Psychiatry, University of Maryland, 220 Arch St, Baltimore, MD 21201 (jzito@rx.umaryland.edu).

Published Online: June 22, 2016. doi:10.1001/jamapsychiatry.2016.1182.

Author Contributions: Dr Zito and Mr Burcu had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Burcu, Zito.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Burcu.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Burcu, Metcalfe.

Obtaining funding: Zito.

Administrative, technical, or material support: Zito, Metcalfe, Underwood.

Study supervision: Zito, Metcalfe, Underwood, Safer.

Conflict of Interest Disclosures: None reported.

Funding/Support: This study was supported by the Blue Cross and Blue Shield of Illinois, Montana, New Mexico, Oklahoma, and Texas.

Role of the Funder/Sponsor: The funding source had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The opinions expressed in this research letter are those of the authors and do not necessarily represent the opinions of the Blue Cross Blue Shield of Illinois, Montana, New Mexico, Oklahoma, and Texas.

Additional Contributions: We thank Lan Vu, senior data science consultant, Blue Cross Blue Shield of Illinois, Montana, New Mexico, Oklahoma, and Texas, for her assistance in data management. No compensation was received for such specific contributions.