Cannabis carries both real risks and real therapeutic potential, but causal evidence is still largely missing
A balanced review found cannabis use is associated with respiratory, cardiovascular, cognitive, and psychiatric harms, but causal relationships are mostly unestablished, while therapeutic potential for cannabinoid-based drugs spans a wide range of conditions.
Quick Facts
What This Study Found
Repeated cannabis use is associated with respiratory and cardiovascular disorders, cognitive alterations, psychosis, schizophrenia, and mood disorders. However, causal relationships are largely missing. Simultaneously, cannabinoid-based drugs show promising therapeutic potential for neurological and psychiatric disorders. Both the popularity and the evidence gaps are growing.
Key Numbers
Cannabis is the most popular illicit drug in the Western world. Associated harms include respiratory, cardiovascular, cognitive, and psychiatric effects. Causal relationships are not established for most. Therapeutic potential spans neurological and psychiatric conditions.
How They Did This
Contemporary narrative review covering adverse effects, safety, and therapeutic potential of cannabis and cannabinoid-based drugs.
Why This Research Matters
Cannabis policy often operates in the space between demonstrated associations and unproven causation. This review honestly addresses both sides, providing a framework for conversations about cannabis that acknowledge uncertainty rather than treating the science as settled.
The Bigger Picture
The cannabis debate is often polarized between those who emphasize harms and those who emphasize benefits. This review makes the case that both perspectives have evidence behind them, and the key unanswered question is causation.
What This Study Doesn't Tell Us
Narrative review without systematic methodology. The balance between harms and benefits varies by condition, dose, and population. "Causal relations missing" does not mean no causation exists.
Questions This Raises
- ?Will longitudinal studies establish causation for the observed associations?
- ?How should clinical and policy decisions be made in the face of this uncertainty?
- ?Can therapeutic benefits be separated from recreational risks?
Trust & Context
- Key Stat:
- Causal evidence still missing
- Evidence Grade:
- Rated moderate because the review provides a fair synthesis of the field, though narrative format limits systematic rigor.
- Study Age:
- Published in 2019.
- Original Title:
- Positive and Negative Effects of Cannabis and Cannabinoids on Health.
- Published In:
- Clinical pharmacology and therapeutics, 105(5), 1139-1147 (2019)
- Authors:
- Cohen, Koby(4), Weizman, Abraham(7), Weinstein, Aviv(5)
- Database ID:
- RTHC-01988
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is cannabis harmful?
It is associated with respiratory, cardiovascular, cognitive, and psychiatric effects, but causal relationships have not been definitively established for most of these.
Does cannabis have legitimate medical uses?
Yes. Cannabinoid-based drugs show promising therapeutic potential for multiple conditions. The challenge is maximizing benefits while minimizing risks, which requires better evidence than currently exists.
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Cite This Study
https://rethinkthc.com/research/RTHC-01988APA
Cohen, Koby; Weizman, Abraham; Weinstein, Aviv. (2019). Positive and Negative Effects of Cannabis and Cannabinoids on Health.. Clinical pharmacology and therapeutics, 105(5), 1139-1147. https://doi.org/10.1002/cpt.1381
MLA
Cohen, Koby, et al. "Positive and Negative Effects of Cannabis and Cannabinoids on Health.." Clinical pharmacology and therapeutics, 2019. https://doi.org/10.1002/cpt.1381
RethinkTHC
RethinkTHC Research Database. "Positive and Negative Effects of Cannabis and Cannabinoids o..." RTHC-01988. Retrieved from https://rethinkthc.com/research/cohen-2019-positive-and-negative-effects
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.