Alcohol, even after one or two drinks, can damage the brain; when a person abuses alcohol, the damages become irreversible. Alcohol is a central nervous depressant, which decreases activity in the cerebral cortex, reticular formation, spinal cord and cerebellum. Alcohol can also interfere in normal neurotransmitter function. Due to its size and water solubility, alcohol can pass through the blood brain barrier and directly affect the brain. The damage from alcoholism can range from temporary impaired judgment to permanent memory loss.
Impaired Cognitive Functions
The University of Washington states that alcohol reaches the brain before the liver, so the effects on the brain can be felt after the first drink. A user has slowed reflexes and problems with coordination. Cognitive functions can be further impaired with poor judgment and problems concentrating. In larger amounts, alcohol causes the person to black out, resulting in memory lapses. If the person drinks too much, she can lose consciousness or even end up in a coma.
Neurotransmitter Interference
When a person drinks alcohol, the molecules enter the brain and interfere in the activity of the neurotransmitter. For example, the University of Washington notes that alcohol increases the production and use of norepinephrine and dopamine, two neurotransmitters involved in mood. Dopamine is also associated with pleasure and is a neurotransmitter responsible for addiction. The GABA systems also have increased activity because alcohol binds to the GABA receptor. Alcohol also increases the production of beta-endorphin in the hypothalamus, a part of the limbic system that regulates hormones. The acetylcholine systems, however, have a decrease in transmission when alcohol is used.
Wernicke-Korsakoff Syndrome
The National Institute on Alcohol Abuse and Alcoholism (NIAAA) states that 80 percent of alcoholics develop a thiamine deficiency from drinking. This leads to a serious condition called Wernicke-Korsakoff syndrome, which results in irreversible damage to the brain. The first half of the syndrome, Wernicke's encephalopathy, causes muscle coordination problems, confusion and paralysis of the abducens nerve. The NIAAA adds that 80 to 90 percent of alcoholics with Wernicke's encephalopathy develop Korsakoff's psychosis, which results in retrograde amnesia in which the patient cannot recall memories and anterograde amnesia in which the patient cannot form new memories. To compensate for the loss of memories, the patient confabulates, a condition in which the patient makes up stories he believes to be true.
