The Cognitive Performance of Unmedicated Off-Prescription Users of Modafinil and Methylphenidate

Abstract Studies suggest that poorer self-reported cognitive functions motivate the off-prescription use of cognitive-enhancing drugs. However, such self-reports may indicate perceived, rather than actual, poorer cognitive performance. To explore this issue, in the current study, we tested the unmedicated cognitive performance of cognitive-enhancing drug (CED) users and non-users using objective and subjective measures. Ninety participants completed the lab-based study, of whom 43 were not CED users, and 47 were CED users. All participants completed demographics and drug use questions, the antisaccade task, the flanker task, and the Behaviour Rating Inventory of Executive Function–Adult Version. The results indicated that CED use was associated with faster and equally accurate automatic responding and faster time to correct errors on objective tests of performance. Being a CED user was not associated with any self-report measures of executive function. These findings suggest that the participants who were CED users did not have poorer cognitive functions for which they may be self-medicating. Instead, these participants may be enhancing their existing healthy cognitive functions. The data reported here suggest that some CED use may be motivated by optimisation of function and not self-medication of problems, perceived or otherwise, with the endogenous control of attention. Cognitive-enhancing drug users are not, therefore, a homogenous group, and the heterogeneity found in the current study has implications for policy or publicity materials aimed at reducing risks associated with this type of drug use.