Effects of Experimental Negative Affect Manipulations on \u3cem\u3eAd Libitum\u3c/em\u3e Smoking: a Meta-analysis

Aims: To quantify the effect of negative affect (NA), when manipulated experimentally, upon smoking as measured within laboratory paradigms. Quantitative meta-analyses tested the effects of NA versus neutral conditions on (1) latency to smoke and (2) number of puffs taken. Methods: Twelve experimental studies tested the influence of NA induction, relative to a neutral control condition (n = 1190; range = 24–235). Those providing relevant data contributed to separate random-effects meta-analyses to examine the effects of NA on two primary smoking measures: (1) latency to smoke (nine studies) and (2) number of puffs taken during ad libitum smoking (11 studies). Hedge\u27s g was calculated for all studies through the use of post-NA cue responses relative to post-neutral cue responses. This effect size estimate is similar to Cohen\u27s d, but corrects for small sample size bias. Results: NA reliably decreased latency to smoke (g = –0.14; CI = –0.23 to –0.04; P = 0.007) and increased number of puffs taken (g = 0.14; CI = 0.02 to 0.25; P = 0.02). There was considerable variability across studies for both outcomes (I2 = 51 and 65% for latency and consumption, respectively). Potential publication bias was indicated for both outcomes, and adjusted effect sizes were smaller and no longer statistically significant. Conclusions: In experimental laboratory studies of smokers, negative affect appears to reduce latency to smoking and increase number of puffs taken, but this could be due to publication bias