Consuming alcohol impairs the brain by altering the neurotransmitters in the brain that control behavior, emotion and thought process. For example, alcohol suppresses glutamate that leads to a decrease in brain activity and energy. Moreover, alcohol increases the inhibitory neurotransmitter GABA, which results in further sedation. The overall result of this activity is a depressed mental state that slows down speech.
The effects of alcohol depends on how much and how often one consumes alcohol, as there are long- and short-term effects of alcohol on the brain, states the National Institute on Alcohol Abuse and Alcoholism. Heavy drinking impairs the brain's ability to create and store memories, resulting in blackouts and memory lapses.
Regular alcohol abuse and alcoholism can result in permanent brain damage. Permanent brain damage can result from direct or indirect alcohol consumption that leads to serious impairments of the brain. For example, alcoholics suffer from a thiamine deficiency, which impairs brain function. An uncorrected thiamine deficiency results in Wernicke–Korsakoff syndrome, a serious brain disorder. Wernicke–Korsakoff syndrome causes psychosis, mental confusion, ocular nerve paralysis and impaired learning skills.
Alcohol causes less severe impairments, such as dysfunctional motor skills, impulsive behavior and poor judgment. Less severe symptoms are seen in social drinkers as well as daily drinkers.