Ecstasy users showed mild cognitive deficits in word fluency, processing speed, and memory over one year, while higher cannabis use was paradoxically linked to faster brain processing speed.
Read this if you're interested in how ecstasy and cannabis may differently affect cognitive function over time.
Ecstasy users showed cognitive deficits; higher cannabis use linked to faster brain processing
What the researchers found
Researchers followed three groups for one year: 14 ecstasy polydrug users, 13 cannabis-only users, and 22 drug-free controls, measuring cognitive performance and brain event-related potentials (P300/P3).
After one year, ecstasy users showed significant cognitive deficits compared to controls in word fluency, processing speed, and memory recognition. Lifetime ecstasy use specifically correlated with poorer memory recognition.
No significant cognitive differences emerged between ecstasy users and cannabis users, or between cannabis users and controls, though this may reflect the small sample sizes.
A paradoxical finding emerged in the brain recordings: higher lifetime cannabis use was associated with faster P3 latency (faster brain processing), opposite to what would be expected if cannabis caused cognitive impairment. No P3 differences were found between any groups.
The authors suggested that the dynamic interaction between ecstasy and cannabis effects may account for the cognitive patterns observed.
Why it matters
This study attempted to disentangle the cognitive effects of ecstasy and cannabis in polydrug users. The finding that cognitive deficits were attributed more to ecstasy than cannabis, combined with the paradoxical P3 finding, suggests cannabis's cognitive effects may be more nuanced than simple impairment.
The numbers in context
14 ecstasy users, 13 cannabis users, 22 controls. 1-year follow-up. Ecstasy users showed deficits in word fluency, processing speed, and memory recognition. Cannabis use correlated with faster (not slower) P3 latency. No P3 group differences.
How the study worked
Longitudinal study with two evaluations one year apart. Auditory P300 event-related potentials and a cognitive test battery were administered to 14 ecstasy polydrug users, 13 cannabis users, and 22 controls.
What this study cannot tell us
Very small sample sizes limit statistical power and generalizability. Ecstasy users were polydrug users, making attribution difficult. Self-reported drug use may be inaccurate. The paradoxical cannabis P3 finding needs replication.
How to read the evidence
This is a longitudinal study with appropriate controls, but the very small sample sizes (13-22 per group) severely limit the strength of the evidence.
When this study was published
Published in 2008. Larger studies have since examined ecstasy and cannabis cognitive effects with more nuanced findings.
The bigger picture
The study highlighted the challenge of studying cannabis effects in polydrug-using populations. The paradoxical P3 finding with cannabis adds to the complex and sometimes contradictory literature on cannabis and cognitive function.
Questions still open
- Does cannabis actually have different cognitive effects than ecstasy, or are the differences due to patterns of use? What explains the paradoxical association between cannabis use and faster brain processing?
Common questions
What is the P300/P3?
Could cannabis protect against ecstasy's cognitive effects?
Read the original research
Auditory event-related potentials (P3) and cognitive performance in recreational ecstasy polydrug users: evidence from a 12-month longitudinal study.
Psychopharmacology, 200(3), 425-37
Citation
de Sola, Susana; Tarancón, Thais; Peña-Casanova, Jordi; Espadaler, Josep María; Langohr, Klaus; Poudevida, Sandra; Farré, Magí; Verdejo-García, Antonio; de la Torre, Rafael. (2008). Auditory event-related potentials (P3) and cognitive performance in recreational ecstasy polydrug users: evidence from a 12-month longitudinal study.. Psychopharmacology, 200(3), 425-37. https://doi.org/10.1007/s00213-008-1217-5
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