Balancing risks and benefits of cannabis use: umbrella review of meta-analyses of randomised controlled trials and observational studies

★

☆

SHARE

Overview

Paper Summary

Conflicts of Interest

Identified Weaknesses

Rating Explanation

Good to know

Topic Hierarchy

File Information

Paper Summary

Paperzilla title

Cannabidiol May Help With Epilepsy But Cannabis Linked To Psychosis: An Umbrella Review

This umbrella review encompassing both observational studies and randomized controlled trials indicates that cannabis use, particularly high-THC cannabis, is linked to an elevated risk of psychosis and other mental health problems, while cannabidiol may be useful in treating certain types of epilepsy. Cannabis-based medicines can reduce seizures in some forms of epilepsy and may be beneficial for pain and spasticity in multiple sclerosis and chronic pain in other conditions, though they are not without adverse effects such as somnolence and visual impairment.

Possible Conflicts of Interest

MS received honoraria/has been a consultant for AbbVie, Angelini, Lundbeck, Otsuka. DC has received grant monies and/or travel support and/or honoraria for talks and consultancy from Eli Lilly, Janssen Cilag, Roche, Allergen, Bristol-Myers Squibb, Pfizer, Lundbeck, Astra Zeneca, Hospira, Organon, Sanofi-Aventis, Wyeth, Hospira, Servier, and Seqirus. He is founder of the Optimal Health Program and part owner of Clarity Healthcare. He is on the scientific advisory of The Mental Health Foundation of Australia. EV has received grants and served as consultant, advisor, or CME speaker for numerous entities outside of the submitted work. CUC has been a consultant or advisor to or received honoraria from numerous pharmaceutical companies, has provided expert testimony, and is a stock option holder for several companies.

Identified Weaknesses

Overreliance on meta-analyses of observational studies

The authors included many meta-analyses of observational studies which are more likely to be affected by confounding factors that reduce the certainty of the results.

Evidence not representative of current products

The content of THC and other cannabinoids is increasingly potent in products purchased in both legal and illegal markets today compared to a decade or more ago.

High-THC cannabis could lead to underestimation of harm

This may result in the authors underestimating the harmful effects of cannabis.

High loss to follow-up in cannabidiol clinical trial

Loss to follow-up reduces the strength of the evidence.

Very short follow-up

A short follow-up period limits the ability to determine the long-term effects of cannabis.

High heterogeneity in some analyses

Heterogeneity limits the generalizability of the findings.

Rating Explanation

This is a well-conducted and informative umbrella review with some limitations. The inclusion of both RCTs and observational studies, quantitative criteria for grading evidence, and consideration of converging evidence are key strengths. However, the overreliance on observational studies, lack of recent evidence reflecting current cannabis products, and high heterogeneity in some analyses limit the generalizability and strength of some of the conclusions. Potential conflicts of interest among several authors are also noted.

Good to know

This is our free standard analysis. Paperzilla Pro fact-checks every citation, researches author backgrounds and funding sources, and uses advanced AI reasoning for more thorough insights.

Explore Pro →