Scientists at the Spanish Institute of Neuroscience have determined that long-term alcohol consumption radically alters the expression of genes responsible for the brain’s reward system, impulse control, and decision-making processes.
The study, published in the journal Addiction, is based on the analysis of post-mortem brain tissue from individuals who had chronically consumed alcohol for an average of 35 years.
The researchers focused on the endocannabinoid system—a neurobiological network that regulates pleasure, mood, memory, and stress response. The study showed that alcohol causes a serious imbalance in this system. Specifically, in the prefrontal cortex (responsible for planning and judgment), the expression of the CB1 receptor gene increased by 125%, while in the nucleus accumbens (the reward center), it rose by 78%. The CB1 receptor is directly linked to the intensification of addictive behavior and the risk of relapse.
In contrast, the expression of the CB2 receptor gene decreased by approximately 50% in both regions. Since the CB2 receptor has neuroprotective and anti-inflammatory functions, its reduction indicates that the brain’s defense mechanisms against alcohol-induced damage are weakened. The study also documented, for the first time, changes in the GPR55 receptor, whose expression increased in the prefrontal cortex but sharply decreased in the nucleus accumbens.
Additionally, scientists discovered changes in the activity of the FAAH enzyme, which is responsible for breaking down anandamide (the body’s natural “bliss molecule”). These findings explain why individuals with alcohol dependence struggle with impulse control and why they are more vulnerable to relapse.
