The influence of nicotine metabolic rate on working memory over 6 hours of abstinence from nicotine

Abstract

Background: A faster rate of nicotine metabolism has been associated with smoking more cigarettes, greater nicotine withdrawal symptoms, and lower smoking quit rates. However, the association between nicotine metabolic rate (NMR) and cognitive functioning during withdrawal has not been determined.

Methods: We compared cognitive function in 121 fast or slow nicotine metabolizers after smoking, and at 3 and 6 h of nicotine abstinence. Cognitive functioning was assessed using N-back working memory tests with outcomes of accuracy and processing speed. Participants smoked two cigarettes and then abstained from smoking for 6 h. N-back tests were administered after smoking (0 h) and at 3 and 6 h of nicotine abstinence.

Results: An effect of processing speed was found over time on the 2-back, in that participants had significantly longer average reaction times when the stimuli presented did not match the target letter. NMR was not significantly associated with the processing speed change over time. Within-race differences in working memory were evident in that Caucasian fast metabolizers had significantly poorer accuracy and processing speed.

Conclusions: Minimal change in working memory over 6 h of nicotine abstinence was observed. Overall, NMR was not significantly associated with the change in processing speed, however Caucasian fast metabolizers displayed poorer accuracy and processing speed at discrete time points.

Trial registration: ClinicalTrials.gov NCT01627392.

Keywords: Cognition; NMR; Nicotine; Nicotine metabolite ratio; Smoking; Working memory.

Conflict of interest statement

Conflicts of interest: NLB is a consultant to Pfizer and Achieve Life Sciences, companies that market or are developing medications to aid smoking cessation and has served as a paid expert witness in litigation against tobacco companies. The other authors have no conflicts to declare.

Copyright © 2019 Elsevier Inc. All rights reserved.

Figures

Figure 1.. Mean Nicotine Levels by Fast and Slow NMR, Pre-Smoking (Baseline) and After Smoking (0, 3 and 6 Hours Abstinence)

*Fast vs. Slow NMR (Nicotine Metabolite Ratio)