Treatment adherence in a smoking cessation clinical trial for individuals with current or past major depressive disorder: Predictors and association with cessation

Effect of early medication adherence on behavioral treatment utilization and smoking cessation among individuals with current or past major depressive disorder

SIGNIFICANCE

Little is known about the mechanisms by which medication adherence promotes smoking cessation among adults with MDD. We tested the hypothesis that early adherence promotes abstinence by increasing behavioral treatment (BT) utilization.

METHODS

Data for this post-hoc analysis were from a randomized trial of 149 adults with current or past MDD treated with BT and either varenicline (n = 81) or placebo (n = 68). Arms were matched on medication regimen. Early medication adherence was measured by the number of days in which medication was taken at the prescribed dose during the first six of 12 weeks of pharmacological treatment (weeks 2-7). BT consisted of eight 45-minute sessions (weeks 1-12). Bioverified abstinence was assessed at end-of-treatment (week 14). A regression-based approach was used to test whether the effect of early medication adherence on abstinence was mediated by BT utilization.

RESULTS

Among 141 participants who initiated the medication regimen, BT utilization mediated the effect of early medication adherence on abstinencea) an interquartile increase in early medication days from 20 to 42 predicted a 4.2 times increase in abstinence (Total Risk Ratio (RR) = 4.24, 95% CI = 2.32-13.37; p <.001); b) increases in BT sessions predicted by such an increase in early medication days were associated with a 2.7 times increase in abstinence (Indirect RR = 2.73, 95% CI = 1.54-7.58; p <.001); and c) early medication adherence effects on abstinence were attenuated, controlling for BT (Direct RR = 1.55, 95% CI = 0.83-4.23, p =.17).

CONCLUSIONS

The effect of early medication adherence on abstinence in individuals with current or past MDD is mediated by intensive BT utilization.

Association of anxiety and depression symptoms with perceived health risk of nicotine vaping products for smoking cessation

As tobacco smoking prevalence is unacceptably high for the one in five Australians reporting a mental health condition in the past year, multiple cessation supports are needed to reduce tobacco-related disease. Nicotine vaping product (NVP)-facilitated smoking cessation is one option requiring a medical prescription in Australia. Yet, people easily obtain NVPs via non-prescription channels. As mental health impacts quitting intentions and health system engagement, this study examined how presence of anxiety and depression symptoms may be associated with perceived health risk of using NVPs from prescription or non-prescription sources for smoking cessation. We used cross-sectional South Australian (15 years +) 2022 survey data on vaping, smoking, anxiety, and depression. Robust linear regression was used to examine the association of anxiety and depression symptoms and nicotine addiction concern on perceived health risk of using NVPs from prescription or non-prescription sources. For prescription NVPs, vaping was associated with lower perceived health risk (b=-0.732). Higher perceived addiction risk was associated with higher perceived health risk from prescription NVPs (b=0.784). For non-prescription NVPs, vaping (b=-0.661) or smoking (b=-0.310) was associated with lower perceived health risk, and higher perceived addiction risk (b=0.733) was associated with a higher perceived health risk. Although anxiety and depression were not directly associated with NVP health risk perceptions, vaping while having depression symptoms was associated with higher perceived health risk ratings for prescription (b=0.700) but not non-prescription sources. People with depression who vape may see health risk barriers in NVP prescription access for smoking cessation, a smoking cessation support gap.