Bloomfield, M. A. | bioRxiv Science

bioRxiv2020

The acute effects of cannabidiol on emotional processing and anxiety: a neurocognitive imaging study

BackgroundThere is growing interest in the therapeutic potential of cannabidiol (CBD) across a range of psychiatric disorders. CBD has been found to reduce anxiety during experimentally-induced stress in anxious individuals and healthy controls. However, the mechanisms underlying the putative anxiolytic effects of CBD are unknown. We therefore sought to investigate the behavioural and neural effects of a single dose of CBD vs. placebo on a range of emotion-related measures to test cognitive-mechanistic models of its effects on anxiety. MethodsWe conducted a randomised, double-blind, placebo-controlled, crossover, acute oral challenge of 600 mg of CBD in 24 healthy participants on emotional processing, with neuroimaging (viewing emotional faces during fMRI) and cognitive (emotional appraisal) measures as well as subjective response to experimentally-induced anxiety. ResultsCBD did not produce effects on BOLD responses to emotional faces, cognitive measures of emotional processing, or modulate experimentally-induced anxiety, relative to placebo. ConclusionsGiven the rising popularity of CBD for its putative medical benefits, further research is warranted to investigate the clinical potential of CBD for the treatment of anxiety disorders.

neuroscience↗

bioRxiv2017

The Effect Of Perinatal Brain Injury On Dopaminergic Function And Hippocampal Volume In Adult Life

BackgroundVery preterm birth (<32 weeks of gestation) is associated with long-lasting brain alterations and an increased risk of psychiatric disorders associated with dopaminergic abnormalities. Preclinical studies have shown perinatal brain injuries, including hippocampal lesions, cause lasting changes in dopamine function, but it is not known if this occurs in humans. The purpose of this study was to determine whether very preterm birth and perinatal brain injury were associated with altered dopamine synthesis and reduced hippocampal volume in humans in adulthood.\n\nMethodsWe compared adults who were born very preterm with associated perinatal brain injury to adults born very preterm without perinatal brain injury, and age-matched controls born at full term using [18F]-DOPA PET and structural MRI imaging.\n\nResultsDopamine synthesis capacity was significantly reduced in the perinatal brain injury group relative to both the group born very preterm without brain injury (Cohens d=1.36, p=0.02) and the control group (Cohens d=1.07, p=0.01). Hippocampal volume was reduced in the perinatal brain injury group relative to controls (Cohens d = 1.17, p = 0.01). There was a significant correlation between hippocampal volume and striatal dopamine synthesis capacity (r = 0.344, p= 0.03).\n\nConclusionsPerinatal brain injury, but not very preterm birth without macroscopic brain injury, is associated with persistent alterations in dopaminergic function and reductions in hippocampal volume. This is the first evidence in humans linking neonatal hippocampal injury to adult dopamine dysfunction, and has implications for understanding the mechanism underlying cognitive impairments and neuropsychiatric disorders following very preterm birth.

neuroscience↗