Several weeks ago, we talked about how mood impacted tobacco use behavior such that smokers experiencing higher-than-average positive moods had lower smoking urges later in the day. We have also talked about how mood can change with quitting smoking.
But how do depressive symptoms impact the success of pharmacologic treatments for tobacco use?
A recently published study evaluated the impact of depressive symptoms on smoking outcomes and whether these outcomes are affected by two commonly used treatments for tobacco dependence, bupropion, and varenicline (Zhang H, et al. Effectiveness of Bupropion and Varenicline for Smokers With Baseline Depressive Symptoms. Nicotine Tob Res. 2023 Apr 6;25(5):937-944. PMID: 36520964).
In this study, investigators analyzed a study enrolling smokers randomized to receive 12 weeks of bupropion or varenicline. They assessed depressive mood with a questionnaire assessing “little interest or pleasure in doing things” or “feeling down depressed or hopeless” on a not at all, several days, more than half the days, or nearly every day scale. The outcome was self-reported quitting assessed at weeks 4, 8, 12, 26 and 52.
Investigators observed that patients with depressive symptoms were less likely to quit at the end of treatment compared to participants who did not have these symptoms. In the varenicline group, quit outcomes did not differ between those with and without depressive symptoms.
However, among the bupropion group, individuals with symptoms of depression had a significantly reduced quit rate compared to those without symptoms.
The overall findings suggest that the presence of any depressive symptoms during quitting affects quit rates differently with the two pharmacotherapies. Interestingly, bupropion, which is an antidepressant, was suggested to be less effective in patients with depression. This is surprising because one may think that bupropion, as an antidepressant, would help more in someone with depression.
How do we make sense of this?
We have known for a long time that antidepressants, like SSRIs (selective serotonin reuptake inhibitors), do not generally work for smoking cessation. On the other hand, bupropion is an effective smoking cessation drug and an antidepressant; however, it has a different mechanism of action than SSRIs.
Bupropion is believed to work for smoking cessation by altering levels of dopamine and norepinephrine at the neurotransmitter level.
The findings suggest that bupropion should not be taken to treat an underlying depression among smokers with the hope that this will increase the likelihood of smoking abstinence.
I believe depressive mood symptoms need to be addressed independently from the medications that we give for smoking cessation. When it comes to tobacco treatment, we are left with the notion that we cannot “kill two birds with one stone.”
If depressive symptoms seem to play a big role in our smoking behavior, then addressing these before we quit smoking may help us be successful when we do.
