Neuropsychological Effects of Placebo Stimulants in College Students

Many college students underestimate or ignore the side-effects associated with nonmedical use of prescription stimulants (NMUPS) and are motivated by hopes of academic enhancement. The present study measured the effect a placebo stimulant and personal expectancies have on subjective physiological changes and cognitive enhancement. Undergraduate college students participated in a two-phase study. Phase 1 (n = 305) involved completing an online survey to gather distal study variables and individual stimulant expectancy data. Phase 2 (n = 166) required students to attend an in-person session where they completed physiological and neuropsychological measures (e.g., Physical Symptom Checklist, Digit Span, Passage Comprehension). Students were randomized to receive a placebo stimulant medication (experimental) or no medication (control). Following a 30-minute absorption period, participants completed another set of physiological and neuropsychological measures. Experimental participants reported significant increases in positive symptoms resulting from the placebo stimulant. Expectancies moderated the impact of the placebo stimulant on Passage Comprehension performance; no other neuropsychological task performance was impacted. Despite subjective reports of feeling the effects of stimulants, task performance was unaffected. Moreover, expectancies may play a small role in perceptions of the effects of stimulants.