Cognitive performance effects of nicotine and industry affiliation: a systematic review.
Level 1 - systematic review of randomized trials
Systematic review of randomized controlled trials
PubMed 32547048 · doi:10.1177/1178221820926545
What was done
The authors conducted a systematic review searching PubMed, EMBASE, PsycINFO, BIOSIS, and Web of Science for peer-reviewed randomized controlled trials published between 2009 and 2016. Eligible studies examined the laboratory effects of nicotine on cognitive performance in healthy adults aged 18 to 60 years who were nonsmokers or minimally deprived smokers (abstaining for 2 hours or less). Study disclosures and tobacco industry documents were examined to determine industry affiliations and evaluate associations with reported outcomes.
What was found
From 3,771 screened abstracts, 32 studies were included. The majority assessed attention (n = 22), reporting non-uniform outcomes: 41% (n = 9) positive, 41% (n = 9) mixed, and 18% (n = 4) no effect. Most study authors had received prior tobacco industry funding (59%; n = 19), but over half of these authors (53%; n = 10) did not report it. No association was found between reported study outcomes and tobacco or pharmaceutical industry funding.
Why it matters
This review demonstrates that nicotine lacks reliable cognitive-enhancing effects in laboratory settings. It also reveals high rates of undisclosed tobacco industry ties among published researchers in this field.
Limits
The review was restricted to studies published between 2009 and 2016 and evaluated only acute laboratory effects in healthy adults with minimal or no deprivation. The authors note the analysis likely underestimates industry influence due to strict inclusion criteria and incomplete pharmaceutical funding data. Quantitative meta-analytic pooling was not reported.
Cited by
- supports A 2020 systematic review found that 59% of researchers publishing studies on nicotine's cognitive benefits had tobacco industry funding, and over half did not disclose it.