11/13/2025
At the base, we find in vitro (cell-based) and animal studies. These are essential for identifying mechanisms of action โ for instance, how cannabinoids interact with endocannabinoid receptors or influence inflammation pathways. However, results from these studies cannot be directly applied to human outcomes.
Above this are case reports and case series, which describe individual or small groups of patients responding to treatment. Many early cannabis findings โ such as observations of reduced seizures or improved sleep โ stem from these uncontrolled narratives. While useful for hypothesis generation, they cannot establish cause and effect.
Next come observational studies, including cohort and cross-sectional designs. These track outcomes in real-world populations, offering insights into usage patterns and associations. For example, longitudinal data on chronic pain patients using medical cannabis have informed dosage guidelines and safety profiles, though such studies remain susceptible to confounding variables.
Near the top of the pyramid sit randomised controlled trials (RCTs) โ considered the gold standard for establishing causality. In cannabis research, RCTs on cannabidiol (CBD) for epilepsy and synthetic cannabinoids for multiple sclerosis have set benchmarks for efficacy and regulatory approval. Their strength lies in blinding, randomisation, and controlled dosing, though high costs and strict licensing make them less common than in other therapeutic areas.
At the apex are systematic reviews and meta-analyses, which synthesise all available evidence to produce high-level conclusions. When conducted with robust methodology, they provide the most reliable picture of clinical efficacy and safety, and are increasingly used by regulators and health agencies to inform prescribing policy.
Understand cannabis research quality, from case reports to RCTs and meta-analyses, and how RWE complements trials in guiding clinical and policy decisions.
