Systematic review of CBD doses and effects in 927 adults across 25 studies | Research

The takeaway

A systematic review of 25 human CBD studies found the most consistent evidence for anxiety, social anxiety disorder, and psychotic disorders, with generally mild side effects but wide variation in dosing.

CBD consumers, clinicians considering CBD prescriptions, and pharmacology researchers.

25 studies, 927 patients: best evidence for anxiety and psychosis

What the researchers found

Across 25 studies (927 patients), CBD showed anxiolytic effects with acute administration and therapeutic effects for social anxiety disorder, psychotic disorder, and substance use disorders. Doses and routes of administration varied widely. Side effects were generally mild, though study quality was often limited.

Why it matters

CBD products are sold at wildly different doses with little guidance. This review provides the first systematic look at what doses have actually been tested in humans and what conditions show the most evidence.

The numbers in context

25 studies; 927 patients (538 men, 389 women); from 5 countries; doses varied significantly across studies.

How the study worked

Systematic review of 25 human studies (22 controlled trials, 3 observational) from PubMed, Embase, and Cochrane, published 2000-2019, examining CBD efficacy and safety in adults.

What this study cannot tell us

Substantial heterogeneity in doses, formulations, and routes of administration; many studies had high risk of bias; limited sample sizes in individual studies.

How to read the evidence

Moderate: systematic methodology across 25 studies, but limited by heterogeneous designs and substantial bias risk.

When this study was published

Published 2020.

The bigger picture

The huge variation in CBD dosing across studies reflects how early this field still is. Without standardized dosing protocols, comparing results across studies remains difficult, which is one reason consumer CBD products vary so widely.

Questions still open

What are the optimal CBD doses for specific conditions? Can standardized dosing protocols be developed for clinical use?

Common questions

What conditions does CBD work best for?

The strongest evidence was for acute anxiety relief, social anxiety disorder, psychotic disorders, and substance use disorders. Evidence for other conditions was more limited.

Is CBD safe?

Across 25 studies, side effects were generally mild. However, doses and formulations varied widely, and long-term safety data are limited.

Read the original research

Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.

Journal of clinical medicine research, 12(3), 129-141

View on PubMed ↗Publisher’s paper ↗

Citation

Larsen, Christian; Shahinas, Jorida. (2020). Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.. Journal of clinical medicine research, 12(3), 129-141. https://doi.org/10.14740/jocmr4090