It’s no secret that stimulant medications such as Adderall that are prescribed to treat symptoms of attention deficit hyperactivity disorder are sometimes used as “study drugs” aimed at boosting cognitive performance.

And emergency room visits linked to misuse of the drug are on the rise, according to a study published Tuesday in the Journal of Clinical Psychiatry.

“Young adults in the 18- to 25-year age range are most likely to misuse these drugs,” says Dr. Ramin Mojtabai, a professor at the Johns Hopkins Bloomberg School of Public Health and senior author of the study.

A common scenario is this: A person who has been prescribed ADHD drugs gives or diverts pills to a friend or family member who may be looking for a mental boost, perhaps to cram for a final or prepare a report. And guess what? This is illegal.

Overall, the study found that nonmedical use of Adderall and generic versions of the drug increased by 67 percent among adults between 2006 and 2011. To read more from Allison Aubrey.