Nearly one in 20 college students may have unlawfully used ADHD medication in the past year, hoping to improve their studying and get better grades. New research from the Dutch Institute for Rational Use of Medicine (IVM) and the Trimbos Institute suggests students often receive the medication from friends, family or other acquaintances without a doctor’s prescription.

The medicines in question are mostly the stimulants methylphenidate, (lis)dexamfetamine and modafinil—the first two classified as hard drugs under Dutch drug laws. All three need a doctor’s prescription to be legally obtained, meaning anyone wrongfully possessing or trading them is punishable under the law.

According to another Trimbos-backed study, four percent of students surveyed were found to have taken ADHD medication on occasion without a doctor’s prescription in the past year, mostly bachelor students between the ages of 22 and 25. Another 5.5 to 22.5 percent of the young adults surveyed said they took ADHD medication without a doctor’s prescription. Most students said they use it when facing deadlines, for exams and thesis-writing.

In the latest research, the Trimbos Institute interviewed more than 20 students who were using ADHD medication improperly. Some suffered from side effects including insomnia, nausea, loss of appetite, palpitations and nervousness. In addition, improper use seemed to lead to psychological dependence, leading students to believe they couldn’t study without it.

The study’s authors say that not all healthcare providers, teachers and drug prevention professionals are aware of the situation and the risks involved and call for more guidelines for health professionals and more careful prescription policy.

They have also published a fact sheet concerning the inappropriate use of ADHD medication, are advising caregivers to be more aware and telling students to consult with their GPs if they are having trouble concentrating.