Alcohol is not an "invention" but a derivative from sugar formed in the natural process of fermentation. In times past shepherds and farmers first noticed "drunk" cattle and (at other times and places) hyperactive goats "going bananas" after nibbling on coffee beans.
People looking for a "natural high" in one way or the other just imitated nature when refining and consuming these substances. The reason some people get "hooked" on alcohol is that they have a natural insufficiency of dopamine and compensate for it in this way.
View an on line demonstration of winemaking in a video clip featured on the reference below. The second site explains more about the addiction process itself. Hope this information helps.
Alcohol is a naturally occuring substance.
A very common microbe, the yeast Saccharomyces cerevisiae, eats the naturally occurring sugars in fruit or grains and excretes alcohol and carbon dioxide. This process is called fermentation. Similar processes occur in the production of both bread and cheese.The juice contained in a bunch of grapes fallen from the vine will naturally ferment due to the yeasts endemic to the vineyard.
Wine and beer are the earliest and most common forms of alcoholic beverages that man 'discovered' and adopted as part of the lifestyle and ritual of early civilisations.
For example, the earliest evidence we yet have of winemaking is found in and around the early city of Chatal Hyuk (in what is modern-day Turkey), dating from the Neolithic B period - about 8,000BC. This is about the same time as man was learning to make pottery.
Beer and wine particularly, were an important part of early religious ritual and continue to be even today. In early times, the effects of alcohol were considered to be evidence of having literally taken the God within.
Distilled alcoholic beverages (spirits) came much later, from around the 12th century AD.
A note on parkerlee's answer... The effects of coffee beans have nothing to do with those of alcohol. Coffee contains caffeine, a stimulant. Alcohol is a sedative on the nervous system. They are in fact opposites.
Along with ParkerLee's answer, alcohol was also often used medicinally. For example, during the Civil War (among others), if a limb must be amputated there was no anesthesia to speak of. So a soldier might get a few swigs of whisky as a 'painkiller' of sorts and a stick to bite on as the limb was being removed.
It was also used to calm women who were "hysterical" (probably just stressed out by today's standards) and as a sleeping aide (thus the word 'nightcap').
Alcohol its Originally its Arabic word (الكحول) which is mean monster in Arabic language. And the alcohol was invented by Arabs long time ago.