Chronic alcohol consumption leads to changes in neural circuits, neurochemistry, and the brain-to-body stress system.

“What I'm saying is that if people are ingesting alcohol chronically, even if it's not every night, there are well-recognized changes in neural circuits, there are well-recognized changes in neurochemistry within the brain, and there are well-recognized changes in the brain-to-body stress system that generally point in three directions, increased stress when people are not drinking, diminished mood and feelings of well-being when people are not drinking, and, as you'll soon learn, changes in the neural circuitry that cause people to want to drink even more in order to get just back to baseline or the place that they were in terms of their stress modulation and in terms of their feelings of mood before they ever started drinking in the first place.”