Cannabis plus opioid co-dependence worsens cognitive impairment beyond opioids alone
People with combined opioid and cannabis dependence showed worse executive function and working memory deficits than those with opioid dependence alone, particularly in category completion and error patterns.
Quick Facts
What This Study Found
The OD+CD group completed significantly fewer categories on the Wisconsin Card Sorting Test than healthy controls and had more non-perseverative errors. Both OD and OD+CD groups showed verbal working memory deficits. Interestingly, the OD+CU (cannabis use without dependence) group performed better than controls on one trail-making measure.
Key Numbers
496 participants (97.5% men). OD+CD: fewer WCST categories completed, more non-perseverative errors than HC. OD and OD+CD: more verbal working memory 2-back errors than HC. OD+CU: fewer TMT-B errors than HC.
How They Did This
Cross-sectional controlled study comparing cognitive function across 268 opioid-dependent (OD), 58 OD with cannabis use (OD+CU), 115 OD with cannabis dependence (OD+CD), and 68 healthy controls using SPM, WCST, IGT, TMT, and n-back tests.
Why This Research Matters
Cannabis is often viewed as relatively benign compared to opioids, but when combined with opioid dependence, cannabis dependence appears to add measurable cognitive burden. This has implications for treatment planning and cognitive rehabilitation.
The Bigger Picture
The unexpected finding that cannabis use (without dependence) was associated with better performance on one measure challenges simple additive models of substance-related cognitive impairment and suggests moderate cannabis use may not compound opioid-related deficits.
What This Study Doesn't Tell Us
Overwhelmingly male sample (97.5%). Cross-sectional design cannot determine if cognitive deficits preceded or resulted from substance use. Cannabis use versus dependence distinction is clinical, not biological.
Questions This Raises
- ?Why did cannabis use (without dependence) appear protective on trail-making performance?
- ?Do the additive cognitive deficits of cannabis+opioid dependence reverse with dual abstinence?
Trust & Context
- Key Stat:
- cannabis dependence combined with opioid dependence produced worse executive function than opioid dependence alone
- Evidence Grade:
- Reasonable sample sizes with appropriate controls and validated neuropsychological tests, but cross-sectional design and overwhelmingly male sample limit generalizability.
- Study Age:
- 2025 publication.
- Original Title:
- Neurocognitive Dysfunctions in People with Concurrent Cannabis Use and Opioid Dependence: A Cross-Sectional, Controlled Study.
- Published In:
- Journal of psychoactive drugs, 57(1), 71-83 (2025)
- Authors:
- Ghosh, Abhishek(6), Shaktan, Alka, Verma, Abhishek, Basu, Debasish, Rana, Devender K, Nehra, Ritu, Ahuja, Chirag K, Modi, Manish, Singh, Paramjit
- Database ID:
- RTHC-06537
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis make opioid-related cognitive problems worse?
Cannabis dependence (not just use) appeared to worsen specific cognitive deficits when combined with opioid dependence, particularly executive function measured by category completion. However, cannabis use without dependence did not show the same pattern.
Why did cannabis users without dependence perform better on one test?
The finding was unexpected and could reflect selection bias (more functional users), or potentially some cognitive benefits of moderate cannabis use. It requires replication before drawing conclusions.
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Cite This Study
https://rethinkthc.com/research/RTHC-06537APA
Ghosh, Abhishek; Shaktan, Alka; Verma, Abhishek; Basu, Debasish; Rana, Devender K; Nehra, Ritu; Ahuja, Chirag K; Modi, Manish; Singh, Paramjit. (2025). Neurocognitive Dysfunctions in People with Concurrent Cannabis Use and Opioid Dependence: A Cross-Sectional, Controlled Study.. Journal of psychoactive drugs, 57(1), 71-83. https://doi.org/10.1080/02791072.2024.2308213
MLA
Ghosh, Abhishek, et al. "Neurocognitive Dysfunctions in People with Concurrent Cannabis Use and Opioid Dependence: A Cross-Sectional, Controlled Study.." Journal of psychoactive drugs, 2025. https://doi.org/10.1080/02791072.2024.2308213
RethinkTHC
RethinkTHC Research Database. "Neurocognitive Dysfunctions in People with Concurrent Cannab..." RTHC-06537. Retrieved from https://rethinkthc.com/research/ghosh-2025-neurocognitive-dysfunctions-in-people
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.