Alcohol is often incorrectly classified as a stimulant or "upper". Alcohol is in fact a tranquilliser which depresses the central nervous system. The short term physical effects depend on the blood-alcohol level. It ranges from mild mood changes to complete loss of coordination, vision, balance and speech. These effects usually wear off in a matter of hours after a person stops drinking.
Brain damage can occur as a result of a vitamin B2 deficiency. A well-known condition, Karsokov's syndrome, is an amnesic disorder which means that people find it difficult to remember past events and to learn new things.