Recent genetic studies have demonstrated that close relatives of an alcoholic are four times more likely to become alcoholics themselves. Furthermore, this risk holds true even for children who were adopted away from their biological families at birth and raised in a non-alcoholic adoptive family, with no knowledge of their biological family's difficulties with alcohol. More research is being done to determine if genetic factors could account for differences in alcohol metabolism that may increase the risk of an individual becoming an alcoholic. The blood-brain barrier does not prevent alcohol from entering the brain, so the brain alcohol level will quickly become equivalent to the blood alcohol level. Still higher alcohol levels may result in coma and death.
Alcohol is well-known to cause sleep disturbances, so that overall sleep quality is affected.
Numbness and tingling may occur in the arms and legs. Two syndromes, which can occur together or separately, are known as Wernicke's and Korsakoff's syndromes . Both are due to the low thiamine levels found in alcoholics. Wernicke's syndrome results in disordered eye movements, very poor balance and difficulty walking, while Korsakoff's syndrome severely affects one's memory, preventing new learning from taking place. Alcohol causes loosening of the muscular ring that prevents the stomach's contents from re-entering the esophagus.