# Cannabinoid Receptor Type 1 Availability in Individuals with a History of Childhood Trauma: A Positron Emission Tomography Study

## TL;DR

This study found that adults with a history of childhood trauma have lower levels of a brain receptor linked to the endocannabinoid system compared to healthy controls.

## Contribution

The study is the first to show reduced CB1R availability in humans with childhood trauma using PET imaging.

## Key findings

- CB1R availability was lower in trauma-affected individuals globally and in the amygdala and hippocampus.
- No significant differences were found in frontal cortex CB1R availability between groups.
- Psychiatric diagnoses and medication use did not affect the observed CB1R differences.

## Abstract

Early life adversity has a lasting impact on the endocannabinoid (eCB) system based on animal models. However, the impact of early life adversity such as childhood trauma (CT) on the eCB system has not been thoroughly studied. We assessed the availability of cannabinoid receptor type 1 (CB1R) in individuals with CT compared to healthy controls without CT (HCs). Cannabinoid receptor type 1 (CB1R) availability was compared in adults with CT (N = 22) and age- and sex-matched HCs (n = 22), using positron emission tomography (PET) imaging with the CB1R-specific radiotracer [11C]OMAR. Using linear models, the effect of the group was assessed on global and trauma-relevant brain regions (amygdala, hippocampus, and frontal cortex). Compared to HCs, lower CB1R availability was observed in CT globally (difference= −11.36%, F(1,42) = 4.35, p = 0.04), in amygdala (−13.70%, F(1,84) = 6.66, p = 0.01), and in hippocampus (−14.50%, F(1,84) = 6.59, p = 0.01), but not in frontal cortex (−8.08%, F(1,84) = 2.17, p = 0.14). There were no effects of a diagnosis of posttraumatic stress disorder, major depressive disorder, nicotine dependence, or the use of antidepressant medication. This preliminary result of lower CB1R availability in adults with CT compared with HCs suggests eCB dysregulation associated with CT. Future studies should replicate and extend this finding and examine the potential effects of various trauma features on the eCB system.