Scientists have identified genes that are commonly inherited across addiction disorders, regardless of what substance was used. The study was led by researchers at the Washington University in St. Louis. In 2021, more than 46 million people in the U.S., at the age of 12 or older, had at least one substance use disorder, with only 6.3% receiving treatment. About 107,000 people died of drug overdoses in 2021, with 37% of the deaths involving opioid and stimulant drug exposure. Disorders caused by substance use are heritable and influenced by interactions among different genes and environmental factors. The genome-wide association is a method that searches entire genomes for regions of genetic variation, called single-nucleotide polymorphisms, that associate with the same disease or condition among multiple people. In the study, researchers used this method to identify areas in the genome that were associated with general addiction risk and risk of substance specific disorders. A sample of 1,025,550 individuals with genes indicating European ancestry was used and so was a sample of 92,630 people with genes indicating African ancestry. The research team discovered various molecular patterns, including 19 independent SNPs associated with general addiction risk and 47 SNPs associated with substance specific disorders. These identified patterns were among the European ancestry. The strongest gene signals that were consistent across the different disorders were located in areas of the genome responsible for regulation of dopamine signaling, indicating that dopamine signaling regulation is an important part of addiction risk. The genomic pattern associated with general addiction risk predicted higher risk of mental and physical illness, including suicidal behaviors, chronic pain conditions, psychiatric disorders, and respiratory conditions. In children aged 9 to 10 years old, the presence of these genes correlated with parental substance use. Genomic analysis in the African ancestry sample showed one SNP associated with general addiction risk and one SNP associated with alcohol use disorder.
This research is very intriguing. Firstly, it’s intriguing in that the results between the different ancestries are drastically different. It could also be taken into account the different sample sizes between the two ancestries. However, due to the sample sizes and the limited research done so far, the data cannot be used to categorize genetic risks within certain populations. But, including populations that have historically been underrepresented in biological and biomedical research could lead to a better accuracy in the found results. Hopefully, this research opens a pathway to discovering the factors that protect or predispose a person to a substance use disorder. Through these findings, the hope is that new treatments and preventative measures could be found against multiple substance use disorders