Large Australian registry showed medicinal cannabis was safe and effective for at least two years
A registry of 3,961 cannabis-naive patients prescribed medicinal cannabis showed sustained safety and significant improvements in pain, mental health, insomnia, and overall health status for over two years.
Quick Facts
What This Study Found
Statistically significant improvements sustained over 2+ years across all outcomes: clinical impression (+39-52%), pain interference and severity (22-26%), depression/anxiety/stress (24-28%), insomnia (35%), and physical/emotional functioning (34-37%). 37.3% experienced adverse events, mostly mild (67%) or moderate (31%), with <2% severe and 0.1% serious.
Key Numbers
3,961 patients. Median daily dose: 10 mg THC, 22.5 mg CBD. 37.3% had adverse events (67% mild, 31% moderate, <2% severe, 0.1% serious). Pain severity improved 22.2%, pain interference 26.1%. Depression 24.5%, anxiety 25.5%, stress 27.7%. Insomnia 35%. Stable dose and concomitant medication count over 2 years.
How They Did This
Prospective longitudinal registry of 3,961 cannabis-naive patients prescribed oral medicinal cannabis at specialized clinics. Mean age 56.07, 51% female, with multimorbidity (mean 5.14 diagnoses) and polypharmacy (mean 6.26 medications). Validated outcomes collected regularly over two years.
Why This Research Matters
This is one of the largest and longest prospective registries of medicinal cannabis patients, providing real-world evidence of sustained safety and effectiveness in a complex patient population.
The Bigger Picture
Real-world registry data from thousands of patients complements the smaller, controlled trials by showing what happens when medicinal cannabis is prescribed to complex, multimorbid patients in routine clinical practice.
What This Study Doesn't Tell Us
Observational registry without placebo control, so improvement could reflect placebo effects, natural disease course, or regression to the mean. Patients self-selected for treatment. Attrition over 2 years may introduce survivor bias.
Questions This Raises
- ?How much of the improvement is attributable to cannabis versus placebo or other factors?
- ?Would benefits persist beyond 2 years?
- ?Does the stable concomitant medication count mean cannabis did not replace other treatments?
Trust & Context
- Key Stat:
- Significant improvements sustained across all outcomes for 2+ years
- Evidence Grade:
- Moderate: large prospective registry with validated outcomes, but no placebo control or randomization.
- Study Age:
- Published in 2022.
- Original Title:
- A large Australian longitudinal cohort registry demonstrates sustained safety and efficacy of oral medicinal cannabis for at least two years.
- Published In:
- PloS one, 17(11), e0272241 (2022)
- Authors:
- Vickery, Alistair W, Roth, Sebastian, Ernenwein, Tracie, Kennedy, Jessica, Washer, Patrizia
- Database ID:
- RTHC-04276
Evidence Hierarchy
Enrolls participants and follows them forward in time.
What do these levels mean? →Frequently Asked Questions
What conditions were treated?
Chronic pain was the most common indication (71.9%), followed by psychiatric conditions (15.4%), neurological conditions (2.1%), and other diagnoses (10.7%).
Were there serious side effects?
Adverse events occurred in 37.3% of patients, but most were mild (67%) or moderate (31%). Less than 2% were severe, and only 2 patients (0.1%) had serious adverse events.
Did patients reduce other medications?
The mean number of concomitant medications did not significantly change over 2 years, suggesting cannabis was used as an add-on rather than a replacement for existing treatments.
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Cite This Study
https://rethinkthc.com/research/RTHC-04276APA
Vickery, Alistair W; Roth, Sebastian; Ernenwein, Tracie; Kennedy, Jessica; Washer, Patrizia. (2022). A large Australian longitudinal cohort registry demonstrates sustained safety and efficacy of oral medicinal cannabis for at least two years.. PloS one, 17(11), e0272241. https://doi.org/10.1371/journal.pone.0272241
MLA
Vickery, Alistair W, et al. "A large Australian longitudinal cohort registry demonstrates sustained safety and efficacy of oral medicinal cannabis for at least two years.." PloS one, 2022. https://doi.org/10.1371/journal.pone.0272241
RethinkTHC
RethinkTHC Research Database. "A large Australian longitudinal cohort registry demonstrates..." RTHC-04276. Retrieved from https://rethinkthc.com/research/vickery-2022-a-large-australian-longitudinal
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.