Cigarette smoking and personality: interrogating causality using Mendelian randomisation

Hannah M. Sallis*, George Davey Smith, Marcus R. Munafò

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

10 Citations (Scopus)
288 Downloads (Pure)


Background: Despite the well-documented association between smoking and personality traits such as neuroticism and extraversion, little is known about the potential causal nature of these findings. If it were possible to unpick the association between personality and smoking, it may be possible to develop tailored smoking interventions that could lead to both improved uptake and efficacy.

Methods: Recent genome-wide association studies (GWAS) have identified variants robustly associated with both smoking phenotypes and personality traits. Here we use publicly available GWAS summary statistics in addition to individual level data from UK Biobank to investigate the link between smoking and personality. We first estimate genetic overlap between traits using LD score regression and then use bidirectional Mendelian randomization methods to unpick the nature of this relationship.

Results: We found clear evidence of a modest genetic correlation between smoking behaviours and both neuroticism and extraversion. We found some evidence that personality traits are causally linked to certain smoking phenotypes: among current smokers each additional neuroticism risk allele was associated with smoking an additional 0.07 cigarettes per day (95% CI: 0.02, 0.12, p=0.009), and each additional extraversion effect allele was associated with an elevated odds of smoking initiation (OR=1.015, 95% CI: 1.01, 1.02, p=9.6x10-7).

Conclusion: We found some evidence for specific causal pathways from personality to smoking phenotypes, and weaker evidence of an association from smoking initiation to personality. These findings could be used to inform future smoking interventions or to tailor existing schemes.
Original languageEnglish
Pages (from-to)2197-2205
Number of pages9
JournalPsychological Medicine
Issue number13
Early online date25 Oct 2018
Publication statusPublished - 1 Oct 2019

Structured keywords

  • Tobacco and Alcohol
  • Physical and Mental Health


  • Extraversion
  • Mendelian randomisation
  • neuroticism
  • personality traits
  • smoking behaviours


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