Gut-Microbiome Implications in Opioid Use Disorder and Related Behaviors

Abstract

Substance use disorder (SUD) is a prevalent disease that has caused hundreds of thousands of deaths and affected the lives of even more. Despite its global impact, there is still no known cure for SUD, or the psychological symptoms associated with drug use. Many of the behavioral consequences of drug use prevent people from breaking the cycle of addiction or cause them to relapse back into the cycle due to the physical and psychological consequences of withdrawal. Current research is aimed at understanding the cause of these drug related behaviors and therapeutically targeting them as a mechanism to break the addiction cycle. Research on opioids suggests that the changes in the microbiome during drug use modulated drug related behaviors and preventing these microbial changes could attenuate behavioral symptoms. This review aims to highlight the relationship between the changes in the microbiome and behavior during opioid treatment, as well as highlight the additional research needed to understand the mechanism in which the microbiome modulates behavior to determine the best therapeutic course of action.

Keywords: behavior; gut-brain; microbiome; opioid use disorder; substance use disorder; withdrawal.

FIGURE 1

This schematic shows the microbial and neuronal changes that occur during drug use. Exposure to drugs cause a dysbiosis of the microbiome and impaired gut barrier function which leads to the translocation of pathogenic bacteria, resulting in a release of pro-inflammatory cytokines. The vagus nerve sends communications from the gut microbiome to the brain. Additionally, within the brain there is an increased activation of microglia and alterations to BDNF signaling. All of these factors seem to play in a role in drug related behavior, leading to tolerance development, addiction and reward signaling, withdrawal symptoms, anxiety, and depression. Image created with BioRender.com.