Salivary cotinine levels in human tobacco smokers predict the attentional validity effect size during smoking abstinence

Rationale: The link between attention and brain cholinergic neurotransmission is widely accepted. Human chronic tobacco smokers maintain high levels of nicotine in plasma and body tissues and show enhanced attentional orienting and other attentional tasks. Objective: We wished to test whether abstinence from smoking caused levels of the nicotine metabolite cotinine to decline and attentional enhancement to be reduced in a correlated manner. Methods: The levels of salivary cotinine and behavioral performance on a cued target detection task were measured in chronic, adult tobacco smokers over a 5-day abstinence period. Control groups assessed over the same time period include non-smokers, smokers that did not abstain from tobacco, and smokers that abstained for 4 days and smoked on the last day. Results: In all groups with tobacco exposure, the levels of cotinine declined steadily with time after abstinence, reaching near zero levels at day 5. During this period, reaction times declined as well for all groups, due in part to task practice effects. In contrast, the validity effect, which indexes attentional. allocation, increased with abstinence and was inversely related to cotinine levels in groups exposed to tobacco. Conclusions: We conclude that 1) nicotine abstinence increases the attentional validity effect, and 2) this increase is indexed by salivary cotinine, and 3) that control levels of attentional performance are achieved after 3-4 days of tobacco abstinence.