SU68. Effect of Cannabis on Neuroinflammation in Clinical High Risk for Psychosis: An In Vivo PET Study With [18F]-FEPPA
Bibliographic record
Abstract
Background: Clinical high risk for psychosis (CHR) is the (putative) prodromal phase of psychosis characterized by attenuated psychotic symptoms and/or genetic risk with recent functional deterioration. Epidemiological evidence suggests that early cannabis use is associated with psychosis particularly in predisposed individuals. However, cannabinoids, including cannabis, have also been suggested to have neuroprotective and anti-inflammatory effects. This is particularly important as neuroinflammation has been implicated in the pathophysiology of several brain disorders including schizophrenia. Neuroinflammation is characterized by microglial activation in the brain. Upon activation, microglia increase the expression of a mitochondrial Translocator protein 18 kDa (TSPO). Therefore, increased TSPO expression represents an important marker of neuroinflammation/microglial activation. The purpose of this study is to image neuroinflammation in vivo in brain in CHR for psychosis with (CHR-CU) and without (CHR) concurrent cannabis use. Methods: Eighteen CHRs and 5 CHR-CUs underwent an MRI and a high-resolution [18F]-FEPPA PET scan to quantify neuroinflammation in vivo in brain. CHR-CUs were included if they met criteria for DSM-V cannabis use disorder and/or current cannabis use as determined by a positive drug screen (at least 3 times weekly for 12 months in lifetime). All participants completed a series of neuropsychological and clinical assessments. PET images were analyzed using the validated 2-tissue compartment model to obtain total distribution volumes (VT) in the hippocampus and dorsolateral prefrontal cortex (DLPFC). Results: No significant differences in [18F]-FEPPA binding were observed between groups (F(2,19) = 1.447, P = .260). In the CHR group, there was a positive correlation between apathy and [18F]-FEPPA binding in the hippocampus (r = 0.543, P = .024) and a trend in the DLPFC (r = 0.475, P = .054). In the CHR-CU group, there was a negative correlation between cumulative cannabis use and [18F]-FEPPA binding in the DLPFC (r = −0.982, P = .018). There were no significant correlations between [18F]-FEPPA binding and measures symptom severity or cognition. Conclusion: This is the first in vivo study to investigate the role of cannabinoids on neuroinflammation, and its relevance for psychosis. Results, although preliminary, suggest no difference in the level of neuroinflammation between CHR-CUs compared to CHRs. Increased sample size is required to confirm the results.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".