Abstract
BACKGROUND AND AIMS: Previous studies on response inhibition deficits in smoking have often been conducted in small, young, age-homogeneous samples, without controlling for covariates or testing moderating effects. The primary research question compared response inhibition between a large, age-diverse smoking sample and non-smoking controls, and examined whether deficits were exacerbated toward smoking-related stimuli. By accounting for key covariates and moderators, this study aimed to extend understanding of individual differences in response inhibition deficits in smoking. DESIGN AND SETTING: Cross-sectional study conducted at a university laboratory in Munich, Germany. PARTICIPANTS: The large (n = 122, 57% female), age-diverse (M(age) = 41.4, range: 21-70 years) smoking group comprised individuals with moderate to severe tobacco dependence participating in a smoking reduction intervention study. Controls comprised n = 69 healthy individuals with no smoking history. MEASUREMENTS: Primary outcomes were commission error (CE) rates and mean reaction times in Go trials (Go-RT) in general and smoking-specific Go/No-Go tasks (GNGTs). Covariates included age, sex and IQ. Smoking-related variables were cigarettes per day (CPD), tobacco dependence severity and craving. FINDINGS: General GNGT: The smoking group exhibited significantly higher CE rates (P-value < 0.001, medium effect, BF(10) = 9.06) than the control group. Higher craving was associated with faster Go-RTs (β = -1.487, P-value = 0.041). Smoking-specific GNGT: CE rates were significantly higher in the smoking group only when controlling for covariates (β = 1.272, P-value = 0.040). Higher craving was associated with higher CE rates during smoking-related trials (β = 0.108, P-value = 0.010). The smoking group showed significantly faster Go-RTs in response to smoking-related compared with neutral stimuli, relative to the control group (β = -3.326, P-value = 0.027). Preliminary evidence indicated that greater deficits were associated with higher scores in smoking-related variables, but only in older individuals. CONCLUSIONS: Individuals who smoke appear to exhibit response inhibition deficits, although these are not uniform and seem to be exacerbated during higher reported craving or in response to smoking-related stimuli. Age may moderate the relationship between deficits and smoking-related variables.