Effects of e‐cigarette use on mental health among youths: quasi‐experimental evidence from Canada
Bibliographic record
Abstract
BACKGROUND AND AIMS: Existing research on mental health comorbidities of youth e-cigarette use is subject to confounding bias and reverse causality. This study aimed to measure the effects of e-cigarette use on youth mental health, using e-cigarette minimum legal age (MLA) law in Canada as a natural experiment. DESIGN: We used difference-in-differences (DD), difference-in-differences-in-differences (DDD) and two-sample instrumental variables (TSIV) methods. SETTING: Data were from nationally representative Canadian Community Health Surveys 2008-2019 and Canadian Student Tobacco Alcohol and Drugs Surveys 2008-2019. PARTICIPANTS: The study sample comprised of respondents aged 15 to 18 (in DD analysis; n = 33 858) and aged 15 to 24 (in DDD analysis; n = 78 689). MEASUREMENTS: Primary outcomes were self-reported mood disorders and anxiety disorders. Secondary outcomes were cannabis use, illicit drug use, cigarette use and strength of peer relationships at schools. FINDINGS: After the e-cigarette MLA laws, risks of mood disorders declined by 1.9 percentage points (95% CI, 0.0-3.8; P = 0.05) in the DD analysis and by 2.6 percentage points (95% CI, 0.2-5.0; P = 0.03) in the DDD analysis. For anxiety disorders, while the DD estimate was negative but imprecisely estimated, the MLA law reduced risks of anxiety disorder by 3.6 percentage points (95% CI, 0.9-6.2; P = 0.01) in the DDD analysis. Youths in provinces with MLA laws were also less likely to report cannabis use and illicit drug use and more likely to feel being part of schools. TSIV analysis indicates that youth e-cigarette use increased the likelihood of mood and anxiety disorders by 44% and 37%, respectively. CONCLUSION AND RELEVANCE: In Canada, the e-cigarette minimum legal age law appears to have reduced risks of mood and anxiety disorders, lowered substance use and improved peer relationships at schools. Combined with previous evidence of lower e-cigarette use following the minimum legal age law, our findings indicate that youth e-cigarette use increases risks of mood and anxiety disorders.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".