There is a high rate of co-morbidity between depression and smoking; rates of smoking are approximately double in those with depression compared with the general population.

In addition, smokers with depression tend to have higher rates of nicotine dependence, suffer greater negative affect during abstinence/withdrawal, are more likely to fail in quit attempts, and are therefore more at risk of smoking-related morbidity and mortality.

Given such issues, it is important to identify ways to make smoking cessation more successful in this patient population; however, health professionals don’t often encourage these patients to quit as they believe depressive symptoms may get worse. The evidence actually suggests the opposite; depressive symptoms are likely to get better in individuals who successfully quit smoking.

Given the associations between smoking, smoking relapse and depression, a Cochrane review was recently published which brings together and examines the existing evidence on smoking cessation programmes with and without mood management components (van der Meer et al., 2013). The review aimed to determine the effectiveness of smoking cessation interventions, with and without mood management components, in smokers with current or past depression.

Methods

Out of 106 studies reviewed, the Cochrane meta-analysis included 49 trials. Included studies were RCTs testing the effectiveness of pharmacological or psychosocial interventions for smoking cessation in smokers with current/past depression. Study participants were adult smokers with current/past depression, defined as major depression (DSM-IV) or depressive symptoms (measured by scales such as Beck’s Depression Inventory).

Results

Dichotomous treatment outcomes were measured via risk ratio (RR), which is calculated by:

An RR greater than 1.0 favours the intervention group (95% confidence intervals [CI] of the RR are also reported).

The primary outcome of interest was smoking status at a minimum of six months from first quit day.

The authors used ‘sustained cessation rates’ where available, i.e., continuous abstinence from quit date or prolonged abstinence (may include lapses which are not regarded as treatment failure). Participants lost to follow-up were assumed to be continuing smoking.

Patients with current depression

1. Analysis of 11 trials (N = 1844) showed a significant positive effect on smoking cessation by adding psychosocial mood management (RR 1.47, CI 1.13-1.92)
2. Due to insufficient data, the effects of antidepressants on smoking cessation only investigated the effect of buproprion. Analysis of 5 trials (N = 410) showed an insignificant positive effect on smoking cessation (RR 1.37, CI 0.83-2.27)
3. One study (N=196) found that nicotine replacement therapy (NRT) compared with placebo had a positive effect on smoking cessation (RR 2.64, CI 0.93 – 7.45).

Patients with past depression

1. Analysis of 13 trials (N = 1469) showed a significant positive effect on smoking cessation (at ≥6 month follow-up) by adding psychosocial mood management (RR 1.41, CI 1.13-1.77)
2. Analysis of 4 trials (N = 404) showed a significant positive effect for the use of bupropion (RR 2.04, CI 1.31-3.18)
3. Analysis of 3 trials (N = 432) showed an insignificant positive effect on smoking cessation by giving NRT (RR 1.17, CI 0.85-1.60)

Some trials investigated the effects of other pharmacotherapies (e.g., naltrexone) and psychosocial treatments (e.g., nurse staged care), however, due to the heterogeneity between trials, no pooled effects could be estimated.

Conclusions

• For individuals with current and past depression, including a psychosocial mood management component to smoking cessation treatments increases the likelihood of successful smoking cessation.
• While bupropion may increase smoking cessation in those with past depression, there is no evidence for increased effectiveness in those with current depression.
• There is not enough evidence to determine the effectiveness of other antidepressants or treatments without specific mood management components (e.g., NRT and psychosocial interventions), for smokers with past/current depression.

Sum up

• Given that smokers with past/current depression tend to be more severely nicotine dependent and struggle more with successfully quitting, it is important to identify interventions which will enhance successful quit attempts.
• Health professionals are encouraged to advise patients with a history of depression to use a smoking cessation programme which includes a mood management component.
• There was a lot of heterogeneity in the trials included in this meta-analysis (e.g., how depression was assessed, outcome measures used) and a lack of information regarding the history of depression (e.g., one episode vs. multiple episodes). These factors limit the implications of this research and highlight that more research is needed in this group of smokers.
• Trials with mood management components tended to include more treatments sessions. Although this may be a reason for increased effectiveness, most studies investigating associations between number of sessions and treatment success have been non-significant, suggesting that it is the inclusion of mood management components that are important.
• The finding that bupropion enhances treatment outcomes in those with past, but not current, depression is counterintuitive. Given the fairly low number of trials investigating this effect, and that the association between enhanced treatment effectiveness in those with past depression was fairly weak, more research is needed to validate this finding.
• Existing evidence is positive for the use of psychosocial smoking interventions without mood management components; however, these trials often exclude smokers with past/current depression. Research is needed to determine whether more general psychosocial interventions can be effective in smokers with some history of depression.
• The overall findings and limitations highlighted by this review reflect those of an earlier review on smoking cessation interventions in patients with depression (Gierisch et al., 2010)

Links

van der Meer RM, Willemsen MC, Smit F, Cuijpers P. Smoking cessation interventions for smokers with current or past depression. Cochrane Database of Systematic Reviews 2013, Issue 8. Art. No.: CD006102. DOI: 10.1002/14651858.CD006102.pub2.

Gierisch JM, Bastian LA, Calhoun PS, McDuffie JR, Williams JW Jr. Comparative Effectiveness of Smoking Cessation Treatments for Patients With Depression: A Systematic Review and Meta-analysis of the Evidence (PDF). VA-ESP Project #09-010; 2010

NICE guidelines on smoking cessation:

http://guidance.nice.org.uk/PH48

http://www.nice.org.uk/nicemedia/pdf/ph010guidance.pdf