Treatment completion and anxiety sensitivity effects on smoking cessation outcomes

•Examined treatment completion and Anxiety Sensitivity (AS) effect on smoking outcomes.•Completers were more likely to be abstinent over time compared with non-completers.•AS-Physical Concerns (AS-PC) was negatively related to being abstinent.•There was an interaction between AS-PC and treatment completion for smoking status over time.•Completers with higher AS-PC had a greater likelihood of being abstainers than non-completers. Treatment completion is associated with abstinence outcomes in smoking cessation interventions. Previous research has stated that anxiety sensitivity (AS) is associated with smoking-related variables and smoking-cessation outcomes. To date, research has not examined the interaction between AS and treatment completion on smoking-cessation outcomes over time. This study aims to examine the main and the interactive effects of treatment completion and AS (total score and specific dimensions) on smoking-cessation outcomes at 3-, 6-, and 12-month follow-ups. The sample consisted of 210 smokers enrolled in an eight-session smoking-cessation cognitive-behavioral treatment (62.1% women; Mage = 45.2, SD = 11.0). Participants were classified as completers (attended the eight treatment sessions) and non-completers (attended ≤ 7 sessions). Abstinence was biochemically confirmed. Main effects indicated that completers had a higher likelihood of being abstinent over time when compared to non-completers. Regarding AS, those with greater AS-Physical Concerns had lower abstinence rates. Besides, a significant interaction between treatment completion, time and AS-Physical Concerns was found. Particularly, completers with greater AS-Physical Concerns had a higher likelihood of being abstainers than non-completers over time, while no significant differences were found for those with lower AS-Physical Concerns. These data highlight the relevance of AS-Physical levels and smoking-cessation treatment completion on abstinence outcomes over time among treatment-seeking smokers.