Chronic cannabis users showed no neuropsychological deficits after 10-30 days of abstinence but were distinguished by higher novelty seeking and impulsive nonconformity compared to non-users.
Cannabis users concerned about cognitive effects, neuropsychologists, addiction researchers, and policymakers
What the researchers found
No significant group differences in neuropsychological performance between chronic cannabis users (n=56), ayahuasca users (n=69), and non-users (n=94) matched for age, education, and IQ; personality traits (novelty seeking, impulsive nonconformity) best distinguished cannabis users.
Why it matters
This challenges the persistent narrative that cannabis causes lasting brain damage — when users are matched for intelligence and education and given time to clear acute effects, cognitive deficits disappear.
The numbers in context
56 cannabis users, 69 ayahuasca users, 94 non-users; matched by age, education, IQ; 10-30 days abstinence required; cannabis users: higher novelty seeking and impulsive nonconformity, lower introvertive anhedonia.
How the study worked
Cross-sectional study comparing matched groups of regular cannabis users, ayahuasca users, and non-users on neuropsychological battery and personality questionnaires after 10-30 days of abstinence.
What this study cannot tell us
Cross-sectional design cannot determine if personality traits preceded or followed cannabis use; self-selected non-treatment-seeking sample; 10-30 day abstinence may not capture very long-term residual effects.
How to read the evidence
Well-matched cross-sectional design with comprehensive neuropsychological battery and validated personality measures, but cannot establish causation or generalize to all users.
When this study was published
Published in 2026 in European Neuropsychopharmacology, contributing to the ongoing debate about cannabis and cognition.
The bigger picture
The finding that personality, not cognition, distinguishes users suggests that some 'cannabis-related' cognitive issues found in other studies may reflect pre-existing traits rather than drug effects.
Questions still open
- Do personality traits predispose to cannabis use, or does long-term use shape personality? Would results differ in treatment-seeking or problematic users?
Common questions
Does long-term cannabis use cause permanent brain damage?
How are cannabis users different from non-users?
Read the original research
Personality, not cognition, distinguishes chronic ayahuasca and cannabis users from non-users.
European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 106, 112782
Citation
Bouso, José Carlos; Andión, Oscar; Estévez, Sabela Fondevila; González, Débora; Alcázar-Córcoles, Miguel Ángel; Kohek, Maja; Santos, Rafael Guimaraes Dos; Hallak, Jaime; Riba, Jordi. (2026). Personality, not cognition, distinguishes chronic ayahuasca and cannabis users from non-users.. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology, 106, 112782. https://doi.org/10.1016/j.euroneuro.2026.112782
Explore the wider topic
- How THC Affects Your Amygdala: The Brain's Threat Detector and Cannabis
- The Anandamide Connection: Your Body's Natural Bliss Molecule
- How Long for Cannabinoid Receptors to Return to Normal
- Cannabis and the Developing Brain: What Every Teenager (and Parent) Should Know
- Why Can't I Enjoy Anything Without Weed? The Science Behind It
- Dopamine Recovery After Quitting Weed: What the Science Says
- The Endocannabinoid System Explained Simply: What It Does and Why It Matters
- Your Endocannabinoid System Explained: Why Withdrawal Happens
- Your Nervous System After Quitting Weed: Fight or Flight
- Using Weed Under 18: What It Does to Your Developing Brain
- What THC Does to Your Brain: Why Withdrawal Happens
- THC and Your Prefrontal Cortex: What Cannabis Does to Your Decision-Making Brain
- Weed, Cortisol, and Stress: What Cannabis Does to Your Stress Hormones
- Weed and Memory: What the Science Says About THC and Your Hippocampus
- Weed and Motivation: Is Amotivational Syndrome Real?
- Weed and Your Nervous System: What THC Actually Does to Your Brain and Body
- How Weed Rewires Your Reward System (And How to Reset It)