Modulation of the effects of amphetamine use on cognition and brain electrophysiology by nicotine use

Abstract

Methamphetamine is widely used worldwide and is the predominant drug in Taiwan. While many studies have looked at differences in cognition associated with amphetamine use, whether these effects are due to amphetamine use alone have been less considered. This means it is difficult to know whether reported differences in cognition are due to methamphetamine use specifically or addiction more generally. Here, inhibitory control and error monitoring were investigated in amphetamine users without cigarette smoking (NSA), amphetamine users with cigarette smoking (SA), and non-smoking controls (NSC) using a drug-cued stop-signal task. For inhibitory control, the NSA group showed the poorest performance. In addition, a negative relationship was found between the number of cigarettes smoked per day and both N2 amplitude and stop-signal reaction time (SSRT), suggesting a link between smoking and improved inhibitory performance. For error-related effects, the SA group showed enhanced Pe responses to drug-related cues, indicating greater error awareness in high-risk contexts. Compared with the NSA group, the SA group demonstrated better inhibitory control and error monitoring, suggesting that smoking may moderate some cognitive deficits associated with amphetamine use. These findings highlight the importance of considering overall substance-use patterns when examining amphetamine-specific effects.