How does alcohol impact the brain

Alcohol impacts the brain in multiple ways. Initially, alcohol crosses the blood-brain barrier due to its solubility and suppresses neuronal activity in the prefrontal cortex, leading to reduced voice modulation and increased impulsive behavior, as well as altered memory formation and storage 1. Chronic drinking, even just once a week, leads to stronger neural circuits that underlie habitual behavior and impulsivity, causing increased habitual and impulsive actions both while drinking and in sober times. Fortunately, abstinence from alcohol can reverse these changes except in cases of prolonged heavy consumption 2.

Alcohol also affects serotonin levels, initially causing hyperactivity of mood circuitries and then a drop in serotonin as alcohol wears off, leading to a cycle of temporary mood elevation followed by decreased mood and further drinking 3. For some individuals, drinking increases alertness, indicating a possible predisposition for alcoholism 4.

In terms of sleep, alcohol suppresses brain activity and sedates the cortex but doesn't promote naturalistic sleep; often mistaken as a sleep aid, it actually prevents proper sleep processes 5. Moreover, even low to moderate alcohol consumption is associated with brain degeneration, specifically the thinning of the neocortex and reduction in neural circuits 6.

Alcohol disrupts the gut-liver-brain axis, leading to leaky gut, the release of inflammatory cytokines, and a propensity for increased alcohol intake due to changes in neuroimmune signaling that affects the regulation of consumption. This unhealthy loop can result in extensive inflammation in the brain and the desire to drink more 7. Overall, the healthiest alcohol intake is zero as drinking has been shown to reduce cortical thickness and shrink gray matter volume in a dose-dependent manner 8.