Long-Term Alcohol Use Rewires Brain Genes, Study Reveals

A new study has uncovered key genetic differences in the brains of people with long-term alcohol dependence. Researchers analysed post-mortem tissue from individuals who had consumed alcohol for around 35 years. The findings highlight changes in genes linked to the brain's reward and control systems.

The research was led by Gabriel Rubio from the Health Research Institute of Hospital 12 de Octubre. Funding came from the Carlos III Health Institute, the Ministry of Science, Innovation, and Universities, the Ministry of Health, and the Alicante Institute for Health and Biomedical Research. The team focused on two brain regions: the prefrontal cortex, which governs decision-making, and the nucleus accumbens, which processes reward.

The study examined genes in the endocannabinoid system, responsible for regulating mood, memory, and stress. Compared to non-addicted individuals, the CB1 receptor gene showed a sharp increase—125% in the prefrontal cortex and 78% in the nucleus accumbens. Meanwhile, the CB2 receptor gene dropped by about 50% in both areas.

Another receptor gene, GPR55, behaved differently across regions. It rose by 19% in the prefrontal cortex but fell by 51% in the nucleus accumbens. The authors suggest these shifts may explain why people with alcohol use disorder struggle with relapse and have weaker executive control.

The results provide new insight into how chronic alcohol use alters brain function at a genetic level. By pinpointing these changes, the study could help shape future treatments for alcohol dependence. The findings also reinforce the link between the endocannabinoid system and addiction vulnerability.