Subconscious threat processing and cannabidiol: A randomized controlled trial.

Abstract

Over the past two decades, neuroimaging researchers have produced strong evidence in support of a network of regions in the human brain which are responsive to socially salient threat signals in the form of fearful facial expressions even when such signals are presented outside the bounds of conscious awareness. Independent of the exploration of the neural substrate of non-conscious threat processing, research into the psychopharmacology of cannabis has revealed a that the major, non-psychoactive cannabinoid found in cannabis – cannabidiol (CBD) – attenuates the normal neural response to consciously presented fearful faces. However, no study to date has examined the effect of cannabidiol on the neural processing of fearful faces presented below the level of conscious awareness. In the current study, I planned to examine the impact of a single, orally administered dose of cannabidiol on the neural response to fearful faces presented below the normal threshold for conscious awareness in the context of a double-blind, placebo-controlled randomized controlled crossover trial in a sample of normal, healthy participants. Based on the literature reviewed in the introduction of Chapter 4, I hypothesized that CBD would attenuate the activity of three distinct brain regions previously implicated in the processing of fearful faces – the amygdala, anterior cingulate cortex, and superior temporal sulcus – while participants view subliminally presented fearful faces. Potential implications are discussed at the conclusion of the manuscript.