Both Cannabis and Ecstasy Users Had Impaired Verbal Memory, but Only Ecstasy Users Had Delayed Memory Deficits
In a three-group comparison, both cannabis and ecstasy users showed verbal memory impairment, but only ecstasy users had additional delayed memory deficits, and neither group recognized their own cognitive problems.
Quick Facts
What This Study Found
Researchers compared cognitive function across three groups of 15 young people: regular ecstasy users, regular cannabis users who had never taken ecstasy, and drug-free controls.
Reaction times (visual, auditory, complex) were similar across all three groups. Visual memory, attention, and concentration also showed no differences.
Verbal memory was impaired in both cannabis users and ecstasy users compared to controls. However, delayed memory (the ability to recall information after a time gap) was impaired only in ecstasy users, distinguishing their cognitive profile from cannabis users.
A notable secondary finding: despite objective cognitive impairments, neither user group reported more cognitive failures in daily life than controls on the Cognitive Failures Questionnaire. Users were not aware of their own deficits.
Key Numbers
Three groups of 15. Verbal memory impaired in both user groups. Delayed memory impaired only in ecstasy users. Reaction times unaffected in all groups. No subjective awareness of cognitive deficits.
How They Did This
Cross-sectional comparison of three groups of 15: ecstasy users, cannabis-only users, and non-users. Wechsler Memory Scale (revised) and computerized reaction time tasks administered while drug-free. Cognitive Failures Questionnaire assessed subjective cognitive complaints.
Why This Research Matters
Unlike the previous ecstasy-cannabis comparison (RTHC-00093) which found no cannabis effects, this study found verbal memory impairment in both groups. The discrepancy highlights how study design, tests used, and population characteristics affect findings. The lack of self-awareness of deficits is clinically important.
The Bigger Picture
The finding that users did not recognize their own cognitive impairments has practical implications: cannabis and ecstasy users may not seek help for cognitive problems because they do not perceive them, and they may engage in complex tasks (driving, studying) while objectively impaired but subjectively unaware.
What This Study Doesn't Tell Us
Very small groups (15 each). Cannabis users varied in frequency and duration of use. Self-reported drug history without verification. Cross-sectional design cannot determine causation. The ecstasy group may have differed from cannabis group in other unmeasured ways.
Questions This Raises
- ?Why did this study find cannabis-related verbal memory effects while the earlier study (RTHC-00093) did not?
- ?Does the lack of self-awareness worsen over time?
- ?Would the verbal memory deficit reverse with abstinence?
Trust & Context
- Key Stat:
- Users were not aware of their own cognitive deficits despite objective impairment
- Evidence Grade:
- A three-group comparison with standardized cognitive testing. Useful design but very small groups (N=15 each) limit statistical power.
- Study Age:
- Published in 2000. Research on cannabis and memory has expanded substantially with larger samples and more sophisticated testing.
- Original Title:
- Cognitive performance amongst recreational users of "ecstasy".
- Published In:
- Psychopharmacology, 151(1), 19-24 (2000)
- Authors:
- Rodgers, J
- Database ID:
- RTHC-00099
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis affect memory?
In this study, cannabis users showed impaired verbal memory compared to non-users. However, delayed memory was unaffected, and cannabis users were not aware of their deficits.
How does cannabis compare to ecstasy for memory?
Both impaired verbal memory, but ecstasy users additionally had impaired delayed memory, suggesting ecstasy causes more extensive memory disruption than cannabis.
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Cite This Study
https://rethinkthc.com/research/RTHC-00099APA
Rodgers, J. (2000). Cognitive performance amongst recreational users of "ecstasy".. Psychopharmacology, 151(1), 19-24.
MLA
Rodgers, J. "Cognitive performance amongst recreational users of "ecstasy".." Psychopharmacology, 2000.
RethinkTHC
RethinkTHC Research Database. "Cognitive performance amongst recreational users of "ecstasy..." RTHC-00099. Retrieved from https://rethinkthc.com/research/rodgers-2000-cognitive-performance-amongst-recreational
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.