UC Riverside

The off-label use of prescription psychostimulants in healthy individuals is becoming more prevalent, particularly in college populations, prompting the new label “Generation Adderall”. Although these drugs have been shown to improve cognition in children with attention-deficit disorder (ADHD), the efficacy of stimulant medications for cognitive enhancement in healthy adults has not been definitively shown, with some research indicating positive effects on cognition, others indicating negative effects, and still others showing no effects of stimulant interventions. Further, discrepant results have been reported between, but also within cognitive domains, suggesting more research is needed to carefully illuminate and replicate these effects. I propose that one of the primary outcomes of psychostimulants, namely decreased sleep, may play an important, and as of yet, unacknowledged role in the effect of these drugs on cognition. Sleep, a basic biological need, has been shown to be important for cognitive processing, including learning, memory and attention. Remarkably, however, the interaction between stimulants, sleep and cognition in healthy adults has received little scientific attention. Here, I first present experimental evidence from two different within-subjects, crossover, double-blind, placebo-controlled studies where I examine the immediate and long-term impact of psychostimulants on two different cognitive domains; sustained attention, which has previously shown stimulant-related performance enhancement, and emotional memory, which has reliably been shown to benefit from sleep. Next, in light of these two studies’ novel contributions, I review the existing literature on stimulant cognitive enhancement and propose a theoretical model that includes sleep as the missing link in the story of psychostimulant cognitive enhancement.