ABSTRACT Background and aims While links between traditional cigarette use and poor mental health are well established, the mental health effects of e-cigarettes (‘vaping’) remain unclear. It is unknown whether adolescents with mental health conditions are more vulnerable to vaping, or if vaping increases the risk of developing mental, behavioural, or neurodevelopmental issues. With rising rates of adolescent vaping and mental health problems, research into their potential relationship is urgently needed. This systematic review synthesises current evidence on the associations between vaping behaviour, internalising and externalising mental health symptoms, risky behaviours (including delinquency, unsafe sexual behaviours, and gateway substance use), and neurodevelopmental outcomes among adolescents and young adults aged 12-24yrs. Methods The review follows the JBI Manual for Systematic Reviews and PRISMA reporting guidelines. Searches were run on Embase, Medline, PsychINFO and the Cochrane Database of Systematic Reviews, using search terms related to vaping/e-cigarettes, mental health, behaviour problems and adolescents and young adults. Both authors screened the search results and full text papers independently. Risk of bias (RoB) and quality assessments were completed with the JBI’s critical appraisal tools and results were presented in tables and figures. Results From 936 unique studies identified in the initial search, 193 full text papers were screened. Twenty-five studies met inclusion criteria, comprising 16 longitudinal cohort studies and 9 cross-sectional. Longitudinal evidence demonstrated that baseline mental health symptom severity, including internalising symptoms (e.g. anxiety and depression) and externalising symptoms (e.g. ADHD and conduct-related difficulties), was associated with initiation of vaping. There was comparatively lower-quality however consistent longitudinal and cross-sectional evidence suggesting that vaping may precede the development or worsening of certain mental health outcomes, including depressive symptoms and suicidal ideation. Vaping was also associated with increased engagement in risky behaviours, including delinquency, unsafe sexual behaviours, cannabis use, and other substance use, with some studies indicating clustering of mental health symptoms and behavioural risk. Substantial methodological heterogeneity was present across studies, and no research directly assessed long-term neurodevelopmental consequences of sustained vaping during adolescence. Conclusions Current evidence provides moderate support for a bidirectional association between vaping behaviour and mental health symptoms among adolescents and young adults. Vaping is also associated with increased engagement in risky behaviours and other substance use, although causality and underlying mechanisms remain unclear. Due to limited high quality evidence, causation cannot be determined. More longitudinal research is needed, especially to assess direction of causality and potential effects on neurodevelopment. Study limitations included methodological inconsistency, ethical concerns, and confounder complexity. These findings can better inform public health policy and future adolescent health research.
Robinson et al. (Mon,) studied this question.