Overall Assessment (7.2/10): The evidence that vaping is associated with worse mental health outcomes is strong and consistent across multiple studies, populations, and countries. The neurobiological mechanisms are well-understood. However, definitive proof of causation remains elusive due to the cross-sectional nature of most research and the impossibility of conducting randomized controlled trials (you can't ethically assign people to vape for years to measure mental health effects).

Practical Takeaway: If you don't use nicotine, don't start — the mental health risks are real. If you're an adult smoker, vaping is a legitimate harm reduction tool, but treat it as a transition, not a destination. If you vape and struggle with anxiety or depression, consider whether the nicotine trap might be part of the problem — and know that quitting produces improvements comparable to antidepressant treatment.