Stimulant Drugs Have Adverse Effects on Cognitive Functioning in Healthy Students

Study of students without an ADHD diagnosis finds that stimulants (Adderall) have little impact on cognitive performance.

Bernalyn Ruiz

A study recently published in the journal Pharmacy reports the findings of a pilot study examining the effects of stimulants on college students who do not meet criteria for a diagnosis of Attention Deficit Hyperactivity Disorder (ADHD). As the authors of the study note, many high school and college students report misusing stimulant medication (e.g. Adderall) to improve their cognitive functioning. In their examination of the drug effects on these students, researchers determined that Adderall did not have a significant effect on cognitive functioning in students without an ADHD diagnosis.

“Contrary to student expectations and beliefs, prescription stimulants may not lead to neurocognitive enhancement and improved academic performance, as stimulant misuse has been found to be negatively correlated with academic functioning,“ the authors write.

Many students report using prescriptions stimulants to give them a cognitive boost. Researchers have found that stimulant misuse is most likely to start in the late teens, with the risk being highest between the ages 16-19. Given that so many students who have not received a diagnosis of ADHD are reporting misuse of these drugs, the researchers of the present study sought to determine if these prescription drugs actually do enhance cognitive functioning in students who do not have an ADHD diagnosis.

To examine if stimulants (Adderall) influence cognitive, autonomic and emotional functioning in healthy college students, Weyandt et al recruited 13 college students and administered either 30 mg of Adderall or placebo. Baseline self-reports and physiological measures were collected prior to “drug” administration. Neurocognitive measures were conducted to assess drug effects on cognition. The tools utilized included tests of working memory, language, attention, executive functioning (self-report), fluency and comprehension. Additional measures of subjective drug effects activated emotion, and autonomic activation (including heart rate and blood pressure) were also included.

Results of the study showed that Adderall had minimal effects on cognition. Medium effects were found on a test of attention and working memory. Small effects were found on tests of executive functioning, attention, language, and perceived drug effect. The authors highlight that while Adderall significantly reduced reaction time, it worsened working memory scores. No effect was found on reading performance.

Lastly, a significant increase was found in activated positive emotion and no effect on negative emotion. Additionally, Adderall had a significant main effect on heart rate and blood pressure.

While the sample of this study was small, and the findings should be interpreted cautiously, they present interesting data that provide some information on the effects of stimulants on individuals without an ADHD diagnosis. Results of the study showed that Adderall had minimal, but mixed effects on cognitive processes, significant effect on autonomic responses (increased heart rate), subjective drug experience, and positive states of activated emotions.

Ultimately, the authors conclude that “non-medical use of moderate-dose Adderall in healthy college students may improve attention ability but has a minimal or adverse impact on other cognitive processes and does not enhance academic performance, despite the common misuse of stimulant drugs for these purposes.”



Weyandt, L. L., White, T. L., Gudmundsdottir, B. G., Nitenson, A. Z., Rathkey, E. S., De Leon, K. A., & Bjorn, S. A. (2018). Neurocognitive, Autonomic, and Mood Effects of Adderall: A Pilot Study of Healthy College Students. Pharmacy6(3), 58. (Link)


  1. Naturally, they neglect to mention that stimulants have the same lack of enhancement of cognitive effect and all the rest on “non-ADHD” students. Judith Rappoport et. al. proved way back in about 1978 that stimulants don’t act differently on “ADHD”-labeled students – they have the same effects on everyone.

  2. I take Adderall XR 30mg. once a day. It definitely helps me. It’s the only thing I take. Because it’s a schedule II “controlled substance” I have to get a prescription every month. My community MH center just can’t seem to handle making sure it’s refilled in a timely manner and I end up going without it an average of 10 days per month. To avoid discontinuation syndrome I skip days in anticipation of thier inability to provide 1 prescription every 30 days. I never had this issue before. It seems simple enough but obviously my nurse practitioner is either incapable of scheduling a reminder and has no idea what it’s like to abruptly stop taking Adderall, or she just doesn’t care. I can definitely tell the difference. So, some days I am better focused and productive. I’m not a scientist but I have personally tested (against my will) every class of psych meds. I can honestly say it makes a positive difference in my life. I have also observed others who take Adderall without a script and it definitely effects them adversely. Frightening really. Although I hate having anything to do with the MH system I go for my Adderall. The alternative is much easier, but illegal and the quality is never the same. I much prefer my name brand Adderall. (I don’t take the generic) In my experience speed does not make other people productive. In fact, it’s a disaster. I don’t buy into the whole ADHD label BS but I do much better on the days I take my Adderall. I know my biology is different.

    • For what it’s worth, the MI Center’s continual screw ups on my drugs so I kept going into withdrawal made me finally decide to come off them. No more physical dependency!

      That wasn’t the ONLY factor. Heart and kidney problems played bigger roles. Plus I always hated the deadening effects. But it did give a sense of urgency since I couldn’t tell when the paper pushing flunkies of the Bureaucratic State would mess up again so I couldn’t get my fix for a week.

  3. ADHD diagnosed people are used to the stimulants, and have built a tolerance. There’s the difference, since non-ADHD students use them only occasionally, so they would be more sensitive to them.

    According to a personal trainer I knew, some runners benefit from drinking a small amount of coffee prior to a run. You would have to time it just right. What happens is that while running, the caffeine level will suddenly drop, which they term “coffee poop-out.” I experienced it once and then, learned. The other drawback to drinking coffee, for some runners, is that it can cause a stomach ache.

    The trainer told me to drink it only if I find it beneficial, but not too early prior to running. I find that I really have to start my run within 45 minutes or it is going to poop out. I can take it or leave it these days.

    To coffee or not to coffee is a major debate among runners, just like the argument over stretching. I do not do the latter, since either before or after running I am likely to overstretch a muscle.

    That said, Runner’s High beats stimulants any day!

    • It was proven decades ago that stimulants don’t affect “ADHD” people any differently than “normal” people. There is no “paradoxical effect,” as seems to be implied by this article’s title. As you say, any difference that may exist is at most attributable to tolerance effects if someone has been using for a while. So if it impairs cognitive performance on “non-ADHD” students, it impairs it for “ADHD” students as well!