People living with multiple sclerosis (MS) who are either current or former smokers were more likely to experience depression and anxiety. Smoking cessation helped ease anxiety, but depression continued to persist for some time. These are the findings of a systematic review published in the journal Multiple Sclerosis and Related Disorders.
Although the association between MS onset and disease progression has been well established, the relationship between smoking behavior and depression/anxiety remains unclear. For the study, researchers sought to look at the evidence on the relationship between current smoking/former smoking and depression/anxiety in people living with MS.
The researchers conducted a systematic review of all relevant quantitative studies that followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. They searched 7 databases for literature associated with psychological conditions in people living with MS from the inception of the database through April 26, 2022.
Inclusion criteria were as follows:
- Study participants ≥18 years of age with a clinical diagnosis of MS;
- Studies that included a sample of current smokers and/or former smokers; and
- Studies that included a quantitative self-report psychometric tool for the assessment of depression and/or anxiety symptoms, validated for the MS population.
Exclusion criteria were as follows:
- Studies not published in English; and
- Reviews, protocols, case studies, editorials, or conference abstracts.
A total of 13 publications that reported on 12 studies fulfilled the study inclusion criteria. Results of the review showed 9 of 12 studies that evaluated current smoking and depression in people living with MS identified a positive association. Four prospective studies offered evidence that supported a causal smoking-depression relationship, with a 1.3-fold to 2.3-fold higher prevalence for depression reported among current smokers compared with nonsmokers.
Additionally, 3 cross-sectional studies found no association between smoking and depression. Further, 4 of 5 studies included in the analysis revealed that current smoking was linked to anxiety, with 3 prospective studies demonstrating that the prevalence of anxiety was approximately 20% higher among current smokers. Further, former smoking was associated with an increased prevalence of depression but not with an increased prevalence of anxiety.
Although several studies evaluated provided evidence of a link between smoking and depression/anxiety, these studies had limitations that might impact the validity of their results. Many of the studies were prone to selection bias and may be representative of cohorts of people living with MS more susceptible to depression and/or anxiety. Studies were also limited by the psychometric tool used, which varied in its precision. Other possible limitations include differences in smoking behaviors and types of tobacco across countries, as well as smoking habits across genders. Additionally, the search strategies used did not include key words for newer methods of inhalation, such as vaping.
Overall, the researchers found a strong association between current and former smoking and depression, and current smoking and anxiety in people living with MS.
The researchers concluded, “Findings may add to the evidence for smoking cessation programs in the treatment of depression and anxiety, and the ongoing use of cognitive-behavioural approaches in promoting smoking cessation.”
Disclosure: One of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of the author’s disclosures.
Vong V, Simpson-Yap S, Phaiju S, et al. The association between tobacco smoking and depression and anxiety in people with multiple sclerosis: a systematic review. Mult Scler Relat Disord. Published online January 4, 2023. doi:10.1016/j.msard.2023.104501