Marijuana use in adolescents altered BDNF levels, with onset age influencing the magnitude of change
Adolescent marijuana use was a significant predictor of altered BDNF levels, and this was not a pre-existing condition but developed secondary to cannabis exposure, with younger users showing different patterns than older ones.
Quick Facts
What This Study Found
Pre-existing BDNF levels did not differ between groups, but marijuana use predicted subsequent BDNF alterations (p=0.001). Younger adolescents showed BDNF increases during early/moderate use. Older adolescents had steeper BDNF increases, especially when escalating use. The findings demonstrate BDNF changes were secondary to marijuana use, not pre-existing.
Key Numbers
500 adolescents; 4 trajectory groups; pre-use BDNF similar across groups (p=0.4); marijuana use significant predictor of BDNF change (p=0.001); younger and older adolescents showed different BDNF response patterns.
How They Did This
Single-site longitudinal cohort of 500 urban healthy adolescents with repeated plasma m-BDNF measurements. Multi-method marijuana use assessment. Group-based trajectory modeling identified four groups: naive (60%), starters (14%), chronic (20%), experimenters/quitters (6%). GLM regression controlled for confounders.
Why This Research Matters
BDNF is essential for brain development and plasticity. This is the first study to show that BDNF changes followed marijuana initiation rather than preceding it, establishing a temporal relationship suggesting causation.
The Bigger Picture
The age-dependent BDNF response suggests the developing brain reacts differently to cannabis depending on its maturational stage. This biological mechanism could explain why younger cannabis users tend to have worse outcomes.
What This Study Doesn't Tell Us
Single-site study. Plasma BDNF may not directly reflect brain BDNF. 500 participants but small subgroups (starters 14%, quitters 6%). Cannot fully exclude all confounders. BDNF has many functions beyond brain development.
Questions This Raises
- ?Do BDNF levels normalize after cannabis cessation?
- ?Does the BDNF alteration pattern predict specific cognitive outcomes?
Trust & Context
- Key Stat:
- BDNF changes followed, not preceded, use
- Evidence Grade:
- Moderate: longitudinal design establishing temporal ordering, but plasma BDNF as a proxy and single-site.
- Study Age:
- Published in 2019.
- Original Title:
- Marijuana use among adolescents is associated with deleterious alterations in mature BDNF.
- Published In:
- AIMS public health, 6(1), 4-14 (2019)
- Database ID:
- RTHC-02178
Evidence Hierarchy
Follows a group of people over time to track how outcomes develop.
What do these levels mean? →Frequently Asked Questions
Does marijuana change the developing brain?
This study found marijuana use altered levels of BDNF, a protein critical for brain development, and confirmed these changes occurred after marijuana use began, not before.
Does the age of first use matter?
Yes, younger and older adolescents showed different patterns of BDNF alteration, suggesting the brain's developmental stage influences how it responds to cannabis.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02178APA
Miguez, Maria Jose; Chan, Wenyaw; Espinoza, Luis; Tarter, Ralph; Perez, Caroline. (2019). Marijuana use among adolescents is associated with deleterious alterations in mature BDNF.. AIMS public health, 6(1), 4-14. https://doi.org/10.3934/publichealth.2019.1.4
MLA
Miguez, Maria Jose, et al. "Marijuana use among adolescents is associated with deleterious alterations in mature BDNF.." AIMS public health, 2019. https://doi.org/10.3934/publichealth.2019.1.4
RethinkTHC
RethinkTHC Research Database. "Marijuana use among adolescents is associated with deleterio..." RTHC-02178. Retrieved from https://rethinkthc.com/research/miguez-2019-marijuana-use-among-adolescents
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.