Cannabis Use and a BDNF Gene Variant Both Predicted Earlier Onset of First Psychosis
Among 260 first-episode psychosis patients, early cannabis use and a specific BDNF gene variant independently predicted younger age at psychosis onset, with early cannabis use significantly associated with male gender.
Quick Facts
What This Study Found
This study investigated whether cannabis use and two genes (COMT Val158Met and BDNF Val66Met) interact to influence when psychosis first appears.
Among 260 Caucasian first-episode psychosis patients, two factors independently predicted younger age at psychosis onset: early cannabis use and carrying the met-allele of the BDNF Val66Met polymorphism.
The BDNF finding is significant because BDNF (brain-derived neurotrophic factor) is critical for brain development and neural plasticity. The met variant reduces BDNF secretion, which could make the developing brain more vulnerable to environmental insults like cannabis.
The COMT gene variant, which has been extensively studied in relation to cannabis and psychosis, did not significantly predict age of onset in this sample.
Notably, early cannabis use was significantly associated with male gender, consistent with the well-documented pattern of earlier and heavier cannabis use among males. This sex-specific pattern may contribute to the earlier psychosis onset often seen in men.
Key Numbers
260 first-episode psychosis patients. Early cannabis use and BDNF met-allele independently predicted younger age at psychosis onset. Early cannabis use significantly associated with male gender. COMT was not significant.
How They Did This
Cross-sectional study of 260 Caucasian first-episode psychosis patients. COMT Val158Met and BDNF Val66Met polymorphisms were genotyped. Early cannabis use, demographics, and age at psychosis onset were assessed. Logistic regression analyzed factors associated with early cannabis use and age at onset.
Why This Research Matters
This study identifies a specific gene-environment interaction that influences when psychosis appears. If BDNF met-carriers are more vulnerable to cannabis-induced acceleration of psychosis, this could enable genetic risk stratification for cannabis use.
The Bigger Picture
The interaction between genetic vulnerability (BDNF met variant) and environmental exposure (early cannabis use) exemplifies how precision psychiatry might approach cannabis risk. Rather than universal warnings, genetic testing could identify individuals at specific risk for cannabis-accelerated psychosis.
What This Study Doesn't Tell Us
Cross-sectional design cannot prove the BDNF variant and cannabis cause earlier psychosis rather than correlating with other factors. The study included only Caucasian patients, limiting ethnic generalizability. Cannabis potency and frequency were not detailed. The sample size may be underpowered for detecting gene-gene interactions.
Questions This Raises
- ?Would BDNF met-carriers who avoid cannabis still develop psychosis at the same age?
- ?Could BDNF-targeted therapies protect against cannabis-induced psychosis risk?
- ?Do other neurotrophic factor genes show similar interactions with cannabis?
Trust & Context
- Key Stat:
- Early cannabis use and BDNF gene variant independently predicted younger psychosis onset
- Evidence Grade:
- Cross-sectional genetic association study in first-episode psychosis patients. Moderate because of adequate sample size and replication of known associations, but cross-sectional design limits causal inference.
- Study Age:
- Published in 2017.
- Original Title:
- Cannabis use, COMT, BDNF and age at first-episode psychosis.
- Published In:
- Psychiatry research, 250, 38-43 (2017)
- Authors:
- Mané, Anna(5), Bergé, Daniel(3), Penzol, Maria Jose, Parellada, Mara, Bioque, Miquel, Lobo, Antonio, González-Pinto, Ana, Corripio, Iluminada, Cabrera, Bibiana, Sánchez-Torres, Ana Maria, Saiz-Ruiz, Jerónimo, Bernardo, Miguel
- Database ID:
- RTHC-01449
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis cause earlier psychosis?
This study found early cannabis use independently predicted younger age at first psychotic episode among 260 patients. Combined with a BDNF gene variant, cannabis use was associated with accelerated onset, though causation cannot be proven from this design.
Does genetics affect cannabis-psychosis risk?
Yes. Carrying the met-allele of the BDNF gene independently predicted younger psychosis onset alongside cannabis use. This suggests some people may be genetically more vulnerable to cannabis-related psychosis acceleration.
Read More on RethinkTHC
- THC-amygdala-anxiety-brain
- anandamide-weed-withdrawal
- cannabinoid-receptors-recovery-time
- cannabis-developing-brain-teenagers
- cant-enjoy-anything-without-weed
- dopamine-recovery-after-quitting-weed
- endocannabinoid-system-explained-simply
- endocannabinoid-system-withdrawal
- nervous-system-weed-withdrawal-fight-flight
- teen-weed-use-under-18-effects-brain
- thc-brain-withdrawal
- thc-prefrontal-cortex-brain-effects
- weed-cortisol-stress-hormones
- weed-memory-loss-recovery
- weed-motivation-amotivational-syndrome
- weed-nervous-system-effects
- weed-reward-system-brain
Cite This Study
https://rethinkthc.com/research/RTHC-01449APA
Mané, Anna; Bergé, Daniel; Penzol, Maria Jose; Parellada, Mara; Bioque, Miquel; Lobo, Antonio; González-Pinto, Ana; Corripio, Iluminada; Cabrera, Bibiana; Sánchez-Torres, Ana Maria; Saiz-Ruiz, Jerónimo; Bernardo, Miguel. (2017). Cannabis use, COMT, BDNF and age at first-episode psychosis.. Psychiatry research, 250, 38-43. https://doi.org/10.1016/j.psychres.2017.01.045
MLA
Mané, Anna, et al. "Cannabis use, COMT, BDNF and age at first-episode psychosis.." Psychiatry research, 2017. https://doi.org/10.1016/j.psychres.2017.01.045
RethinkTHC
RethinkTHC Research Database. "Cannabis use, COMT, BDNF and age at first-episode psychosis." RTHC-01449. Retrieved from https://rethinkthc.com/research/mane-2017-cannabis-use-comt-bdnf
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.