Alcoholism is a chronic remitting and relapsing condition; its aetiology and pathophysiology remains largely obscure despite recent advances. This review summarises the current knowledge about the causation (biological or psychological) of alcohol addiction. This involves heredity, candidate genes, alcohol metabolism regulation and the influence of alcohol in the pathophysiology of the different neurotransmitter systems. Alcohol addiction is a multifactorial phenomenon where personality structure, individual state of mind and social influences are in constant interaction with brain neurobiology and pathophysiology. This disorder influences different sexes in different ways and causes major problems, especially in developed societies.