Genetics and Addiction: Understanding the Complex Interplay

The past decade has seen a significant rise in the prevalence of opioid addiction, reaching epidemic levels. Meanwhile, therapeutic interventions remain limited, highlighting the need for more targeted prevention and treatments. One key question in neuropsychiatry research is why some individuals are more susceptible to addiction. Genetic and environmental factors interplay to determine the likelihood of developing a substance use disorder.

Your Genes and Addiction

Drugs of abuse, such as opioids, affect the brain's reward system, primarily through a neurotransmitter called dopamine. Recent studies have identified specific genetic factors that can increase susceptibility to addiction.

A notable study published in the scientific journal PNAS revealed that a specific type of RNA virus, human endogenous retrovirus-K HML-2 (HK2), integrates into a gene regulating dopamine activity. This integration is more frequently found in individuals with substance use disorders and is associated with drug addiction. This discovery underscores the role of genetics in addiction.

How Stress Induces Epigenetic Changes

Stress can trigger epigenetic changes that influence the development of psychiatric disorders and drug addiction. Epigenetic changes regulate gene expression without altering the DNA sequence.

Stressful situations, such as the loss of a loved one or job, can trigger the release of steroid hormones called glucocorticoids, which alter multiple systems in the body, including the brain's reward circuitry. The interaction between stress hormones and the reward system can trigger addiction and stress-induced relapses.

Stress Reduction and Prevention of Addiction

Fortunately, stress can be mitigated through various factors such as physical activity and social support. These activities produce epigenetic changes that reduce the risk of addiction and can complement other treatments, like cognitive-behavioral therapy and medication for certain individuals.

Physical activity, for instance, can reduce negative feelings and stress-induced epigenetic changes. Engaging in physical activity during a stressful situation, such as the loss of a significant other or job, can decrease the risk of developing addiction or a stress-induced relapse.

Hope for Targeted Treatments

The function and dysfunction of the brain's reward system are complex, plastic, and influenced by both genetic and environmental factors. Understanding these interactions can lead to more efficient prevention and therapeutic approaches. Targeted gene expression alterations can modulate the brain's reward system, potentially leading to reduced self-administration of drugs.

Together, this knowledge can ultimately lead to the development of multilevel and more efficient prevention and therapeutic approaches to address the ongoing opioid epidemic.

Resources:

Human Endogenous Retrovirus-K HML-2 integration within RASGRF2 is associated with intravenous drug abuse and modulates transcription in a cell-line model. Proceedings of the National Academy of Sciences, September 24, 2018.