It seams, intoxication is the most common cause of alcohol-related problems, leading to injuries and premature deaths.
Alcohol is a central nervous system depressant, although in smaller amounts it may appear to have a mild stimulant effect. The main psychoactive ingredient in alcoholic beverages is ethyl alcohol, produced through the fermentation of sugar by yeast. Alcoholic drinks vary in strength, e.g. beer and alcoholic sodas (1-9% alcohol), wines (10-15%) and spirits (35-55%).
The effects of alcohol vary depending on a number of factors including:
· type and quantity of alcohol consumed
· age, weight and gender
· body chemistry
· food in the stomach
· drinking experience
· situation in which drinking occurs
source: http://islamportal.net/article/why-islam-completely-forbidding-consumption-alcohol