Background
Although depression and smoking commonly co-occur, the mechanisms underpinning this association are poorly understood. One hypothesis is that depression promotes tobacco dependence, persistence and relapse by increasing sensitivity to acute negative mood and abstinence induced tobacco-seeking behavior.
Methods
Twenty nine daily smokers of >10 cigarettes per day, nine with major depression and 20 without, completed two laboratory sessions one week apart, smoking as normal prior to session 1 (sated session), and 6 hours abstinent prior to session 2 (abstinent session). In both sessions, tobacco-seeking was measured at baseline by preference to view smoking versus food images. Negative mood was then induced by negative ruminative statements and sad music, before tobacco-seeking was measured again at test.
Results
In the sated session, negative mood induction produced a greater increase in tobacco choice from baseline to test in depressed (p<.001, ηp2=.782) compared to non-depressed smokers (p=.045, ηp2=.216, interaction: p=.046, ηp2=.150). Abstinence also produced a greater increase in baseline tobacco choice between the sated and abstinent sessions in depressed (p=.002, ηp2=.771) compared to non-depressed smokers (p=.22, ηp2=.089, interaction: p=.023, ηp2=.189). These mood and abstinence induced increases in tobacco choice were positively associated with depression symptoms across the sample as a whole (ps≤.04, ηp2≥.159), and correlated with each other (r=.67, p<.001).
Conclusions
Current major depression or depression symptoms may promote tobacco dependence, persistence and relapse by increasing sensitivity to both acute negative mood and abstinence induced tobacco-seeking behavior. Treatments should seek to break the association between adverse states and smoking to cope.