Randomized Controlled Trial (RCT)
The gold standard study design in clinical research. Participants are randomly assigned to treatment or control groups to minimize bias and establish causation.
In Depth
RCTs are considered the highest level of evidence for therapeutic efficacy. In cannabis research, RCTs face unique challenges: difficulty blinding participants to psychoactive effects (unblinding bias), federal Schedule I classification limiting research access in the US, standardization of cannabis products, and ethical concerns about placebo controls in severe conditions. Despite these barriers, the number of cannabis RCTs has grown substantially since 2010, particularly for CBD in epilepsy, pain, and anxiety.
Related Terms
Further Reading
More in Research Methods
Systematic Review
A structured synthesis of all available evidence on a specific research question, using predefined criteria to identify, evaluate, and summarize studies.
Meta-Analysis
A statistical technique that combines quantitative data from multiple studies to produce a pooled estimate of effect size with greater statistical power than any individual study.
Placebo-Controlled
A study design in which the control group receives an inert substance (placebo) identical in appearance to the active treatment, to account for the placebo effect.
Observational Study
A study in which researchers observe participants without intervening. Includes cohort studies, case-control studies, and cross-sectional surveys.
Bioavailability
The fraction of an administered dose that reaches systemic circulation in an active form. Varies substantially by route of administration for cannabinoids.