In 102 cannabis users with recent-onset psychosis, earlier age of first cannabis use was associated with more severe positive symptoms and altered gray matter volume in cerebellar brain networks previously linked to schizophrenia.
Readers interested in how the timing of cannabis use may affect brain development and psychosis risk, particularly the role of the cerebellum.
102 patients from 2 multicentric studies
What the researchers found
Earlier cannabis initiation was linked to greater cerebellar gray matter volume in a network previously identified as altered in schizophrenia, independent of confounders. This cerebellar network was also associated with lower volume in an insula-temporal-frontal network implicated in schizophrenia. Earlier initiation correlated with more severe positive symptoms.
Why it matters
This study connects the timing of cannabis use to specific structural brain network changes that are also seen in schizophrenia, supporting the hypothesis that early cannabis use may disrupt developmental trajectories in a way that increases psychosis risk.
The numbers in context
102 patients with recent-onset psychosis; multicentric data from PRONIA and CIP studies; cerebellar network gray matter volume associated with early cannabis use; correlation with positive symptom severity
How the study worked
Cross-sectional analysis of 102 clinically relevant cannabis users with recent-onset psychosis from the multicentric PRONIA and CIP studies. Source-based morphometry analysis with spatial constraints applied to structural brain networks previously identified as altered in schizophrenia.
What this study cannot tell us
Cross-sectional design cannot determine if brain changes preceded or followed cannabis use. All participants had psychosis, so findings may not generalize to cannabis users without psychosis. Self-reported age of initiation.
How to read the evidence
Multicentric sample with sophisticated neuroimaging analysis, but cross-sectional design and all participants had psychosis.
When this study was published
Published in 2021; longitudinal studies are needed to confirm developmental causation.
The bigger picture
The cerebellum is increasingly recognized as important for cognition and psychosis, not just motor function. Finding that early cannabis use specifically affects cerebellar networks implicated in schizophrenia adds a new dimension to understanding the cannabis-psychosis relationship.
Questions still open
- Do similar cerebellar changes appear in early cannabis users who never develop psychosis? Is there a specific age window during which cannabis use is most likely to affect these brain networks? Are these structural changes reversible with abstinence?
Common questions
Does starting cannabis younger change the brain differently?
Why does the cerebellum matter for psychosis?
Read the original research
Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(8), 1484-1493
Citation
Penzel, Nora; Antonucci, Linda A; Betz, Linda T; Sanfelici, Rachele; Weiske, Johanna; Pogarell, Oliver; Cumming, Paul; Quednow, Boris B; Howes, Oliver; Falkai, Peter; Upthegrove, Rachel; Bertolino, Alessandro; Borgwardt, Stefan; Brambilla, Paolo; Lencer, Rebekka; Meisenzahl, Eva; Rosen, Marlene; Haidl, Theresa; Kambeitz-Ilankovic, Lana; Ruhrmann, Stephan; Salokangas, Raimo R K; Pantelis, Christos; Wood, Stephen J; Koutsouleris, Nikolaos; Kambeitz, Joseph. (2021). Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis.. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(8), 1484-1493. https://doi.org/10.1038/s41386-021-00977-9
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)