E-cigarettes tied to history of poor mental health

Users of electronic nicotine delivery systems are likely to have received a diagnosis of clinical depression in the past, according to a recent study.

“To our knowledge, this study was the first to examine the association between e-cigarette use and depression across several subpopulations in the largest nationally representative database in the United States,” said researchers. “These findings highlight the need for longitudinal studies to examine the association between e-cigarette use and depression, which may be bidirectional.”

Of the 892,394 enrolled participants (aged ≥18 years; 51.3 percent female), only 4.4 percent (n=28,736) were current e-cigarette users. Majority (79.1 percent; n=752,321) had never used the device, while the remaining 16.5 percent (n=111,337) reported past use. Current users were significantly more likely to be also using combustible cigarettes than their nonuser counterparts (51.8 percent vs 7.9 percent). [JAMA Netw Open 2019;2:e1916800]

Multivariable-adjusted logistic regression analysis found that current e-cigarette use was significantly correlated with having been diagnosed with clinical depression (odds ratio [OR], 2.10, 95 percent confidence interval [CI], 1.98–2.23). This effect was stronger in current users who reported daily (OR, 2.39, 95 percent CI, 2.19–2.61) rather than occasional (OR, 1.96, 95 percent CI, 1.82–2.10) device use.

Current e-cigarette use was also significantly indicative of subjective mental health, measured as the number of self-reported number of days with poor mental health (OR, 1.67, 95 percent CI, 1.58–1.76). In absolute terms, current users were almost twice as likely as nonusers to report having one day with bad mental health. Occasional device use (OR, 1.73, 95 percent CI, 1.61–1.85) had a stronger magnitude of impact than daily use (OR, 1.57, 95 percent CI, 1.44–1.70).

Notably, even former device use was associated with both the history of a clinical depression diagnosis (OR, 1.60, 95 percent CI, 1.54–1.67) and having poor subjective mental health (OR, 1.52, 95 percent CI, 1.47–1.57).

Moreover, among never-smokers, current use of e-cigarette likewise increased the likelihood of reporting depression (OR, 2.16, 95 percent CI, 1.87–2.49). The same was true when current smokers who were not using the device were compared to dual users (OR, 2.11, 95 percent CI, 1.94–2.30).

The effect of device use on the likelihood of having been diagnosed with depression remained significant even when the population was stratified according to sex, age and race.

“Our study provides additional evidence to establish an association between e-cigarette use and depression, which could have potentially significant implications for public health, clinical practice and health policy,” the researchers said.

For example, the current findings, along with further confirmatory data, could help tighten regulations around advertising and marketing, as well as provide bases for appropriate warning labels.

“At the very least, our findings warrant careful and thorough evaluation of e-cigarette use in both youth and adults with depression,” the researchers added. “Physicians should consider routine collection of information pertaining to e-cigarette use during clinic visits, especially in patients with depression, and routine counselling for those who use e-cigarettes, offering support to those who express willingness to quit.”