Cannabis Use in Healthy People Linked to Psychosis and Impaired Functioning
A systematic review of 124 studies found that cannabis use in otherwise healthy people was associated with adverse effects on cognition, mood, anxiety, psychosis risk, and social functioning, with the strongest evidence for psychosis and impaired psychosocial functioning.
Quick Facts
What This Study Found
Across 124 studies of cannabis effects in people without psychiatric or medical conditions, frequency of use, THC content, age of onset, and cumulative exposure all contributed to adverse behavioral outcomes including impaired cognition, motivation, mood, anxiety, psychosis risk, and psychosocial functioning.
Key Numbers
2,870 studies screened; 124 included; effects identified across cognition, motivation, impulsivity, mood, anxiety, psychosis, intelligence, and psychosocial functioning; strongest evidence for psychosis and psychosocial functioning; THC (not CBD) content was a key moderator.
How They Did This
PRISMA-guided systematic review of 124 cross-sectional and longitudinal studies (1990-2020) from PubMed and PsycInfo examining cannabis-related adverse behavioral outcomes in subjects without psychiatric or medical comorbidities.
Why This Research Matters
By focusing exclusively on healthy individuals, this review isolates the effects of cannabis from pre-existing conditions, strengthening the case that cannabis itself contributes to these adverse outcomes rather than simply being associated with them.
The Bigger Picture
The finding that THC content, but not CBD, drives adverse behavioral effects has direct implications for cannabis product regulation and suggests that products with higher CBD-to-THC ratios may carry lower behavioral risk.
What This Study Doesn't Tell Us
Systematic review without meta-analysis; heterogeneity in study designs and cannabis exposure measures; cannot fully control for residual confounding even in "healthy" samples; publication bias possible.
Questions This Raises
- ?Could CBD-dominant products avoid the adverse behavioral effects seen with THC-dominant products?
- ?At what threshold of use frequency do behavioral effects become clinically meaningful?
Trust & Context
- Key Stat:
- Strongest evidence for adverse effects was in psychosis risk and psychosocial functioning
- Evidence Grade:
- Large systematic review of exclusively non-clinical populations, strengthened by focus on healthy individuals but limited by heterogeneity.
- Study Age:
- Studies from 1990-2020.
- Original Title:
- The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review.
- Published In:
- Frontiers in psychiatry, 12, 630247 (2021)
- Authors:
- Sorkhou, Maryam(8), Bedder, Rachel H, George, Tony P(23)
- Database ID:
- RTHC-03541
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
Does cannabis harm healthy people?
This review of 124 studies found that cannabis use in otherwise healthy people was associated with adverse effects on cognition, mood, anxiety, psychosis risk, and social functioning, with effects driven by THC content, use frequency, and age of first use.
Does CBD cause the same problems as THC?
No. The review found that THC content, but not CBD, was associated with adverse behavioral outcomes. This suggests that CBD-dominant products may carry lower behavioral risk.
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Cite This Study
https://rethinkthc.com/research/RTHC-03541APA
Sorkhou, Maryam; Bedder, Rachel H; George, Tony P. (2021). The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review.. Frontiers in psychiatry, 12, 630247. https://doi.org/10.3389/fpsyt.2021.630247
MLA
Sorkhou, Maryam, et al. "The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review.." Frontiers in psychiatry, 2021. https://doi.org/10.3389/fpsyt.2021.630247
RethinkTHC
RethinkTHC Research Database. "The Behavioral Sequelae of Cannabis Use in Healthy People: A..." RTHC-03541. Retrieved from https://rethinkthc.com/research/sorkhou-2021-the-behavioral-sequelae-of
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.