Quitting smoking was linked to reduced cannabis use among US veterans | Research

The takeaway

Veterans who quit cigarette smoking had 75% higher odds of also reducing cannabis use two years later, though quitting smoking did not improve psychiatric symptoms or pain.

Veterans using multiple substances, smoking cessation providers, addiction counselors

OR 1.75 for cannabis improvement after quitting smoking

What the researchers found

Quitting smoking was associated with improvement in cannabis use (adjusted OR 1.75, 95% CI 1.00-3.06), unhealthy alcohol use (OR 2.10), and cocaine use (OR 2.25). However, quitting smoking was not associated with improvement in depressive symptoms, anxiety, or pain.

Why it matters

The idea that quitting one substance helps with others has important treatment implications. This study suggests smoking cessation may cascade to reduced cannabis and other substance use, but psychiatric symptoms need separate intervention.

The numbers in context

4,165 eligible smokers, 419 quitters, 2,330 continued smokers. Cannabis improvement OR: 1.75 (1.00-3.06). Alcohol OR: 2.10 (1.01-4.35). Cocaine OR: 2.25 (1.20-4.24). Opioid OR: 1.10 (not significant). Depression OR: 0.78 (not significant).

How the study worked

Emulated hypothetical randomized trial using longitudinal data from the Veterans Aging Cohort Study (2003-2015). Inverse probability weighting adjusted for confounding and selection bias among 4,165 HIV-positive and HIV-negative veteran smokers.

What this study cannot tell us

Emulated trial design does not guarantee causation. Veterans may not represent the general population. Self-reported smoking cessation and substance use. Cannabis improvement was borderline significant (lower CI = 1.00).

How to read the evidence

Emulated trial design with inverse probability weighting is stronger than standard observational, but cannot fully establish causation.

When this study was published

2024 analysis of Veterans Aging Cohort Study data from 2003-2015

The bigger picture

The finding that substance use improved but psychiatric symptoms did not suggests these conditions may have different underlying mechanisms. Smoking cessation programs that add mental health support could address both pathways simultaneously.

Questions still open

Does the substance use improvement sustain beyond two years? Would adding psychiatric treatment to smoking cessation programs improve both substance and mental health outcomes?

Common questions

Does quitting smoking help quit cannabis?

This study found veterans who quit smoking had 75% higher odds of also reducing cannabis use within two years, though the finding was borderline significant.

Did quitting smoking help with depression or anxiety?

No. Despite improved substance use outcomes, quitting smoking was not associated with improvement in depressive symptoms, anxiety symptoms, or pain.

Read the original research

Does smoking cessation reduce other substance use, psychiatric symptoms, and pain symptoms? Results from an emulated hypothetical randomized trial of US veterans.

PloS one, 19(7), e0298576

View on PubMed ↗Publisher’s paper ↗

Citation

Ban, Kaoon Francois; Rogers, Erin; Khan, Maria; Scheidell, Joy; Charles, Dyanna; Bryant, Kendall J; Justice, Amy C; Braithwaite, R Scott; Caniglia, Ellen C. (2024). Does smoking cessation reduce other substance use, psychiatric symptoms, and pain symptoms? Results from an emulated hypothetical randomized trial of US veterans.. PloS one, 19(7), e0298576. https://doi.org/10.1371/journal.pone.0298576