Cannabis effects on cardiovascular health: Current evidence, gaps in knowledge, and future research directions

As cannabis use accelerates globally with expanding legalization and availability of high-potency formulations, concerns regarding its cardiovascular safety have grown. However, the evidence remains unclear and often inconsistent. This narrative review aimed to summarize the current evidence on the cardiovascular effects of cannabis. We performed a narrative review of peer-reviewed studies on cannabis and cardiovascular outcomes, searching PubMed and Google Scholar for relevant human research published 2014-August 2025. Included evidence encompassed observational cohorts, randomized trials, meta-analyses, Mendelian randomization studies, and mechanistic investigations, supplemented by reference screening. Observational studies reveal mixed associations between THC use and myocardial infarction, stroke, and MACE, with many findings attenuated after adjustment for confounders. A stronger and more consistent association exists for atrial arrhythmias. Evidence for venous thromboembolism remains inconsistent. Interpretation of the available evidence is also hindered by exposure misclassification (e.g., dose, route, frequency), reliance on administrative coding, insufficient differentiation between medical and recreational use, residual confounding (e.g., tobacco, other substances), and limited translational data. Cannabis use is rising, and while mechanistic data suggest THC-related autonomic, endothelial, and platelet effects, overall cardiovascular evidence remains mixed with the most consistent signal seen for atrial arrhythmias. Risk appears influenced by dose, route, and co-use of substances, and current studies are limited by heterogeneity and exposure misclassification. Until higher-quality data emerge, clinicians should adopt a precautionary, harm-reduction approach, especially in patients with cardiovascular comorbidities.