Alcoholism, which affects about 7% of the total population, is a socio
sanitary problem with high economic costs and devastating human conseq
uences. This work reviews the biological bases underlying and explaini
ng the capacity that alcohol has to generate addiction and dependence.
Thus, the main pharmacokinetic and pharmacodynamic characteristics of
ethanol, together with its associated unspecific neuropharmacological
effects and the impact on different neurotransmitter systems are pres
ented. It is well established that chronic alcohol consumption generat
es various kinds of organ damage. However, epidemiological studies of
morbimortality cannot ignore individual and sociocultural modulatory f
actors. Therefore, the main alterations on different systems, although
with especial emphasis on anatomical and functional changes in the ne
rvous system, are summarized. Finally, the last section includes the m
ost outstanding results derived from genetic research, aimed to determ
ine phenotypic and genotypic markers of risk for subsequent developmen
t of alcoholism. Even though all known vulnerability factors show spec
ificity problems, future advances in this approach will be the key to
improve prevention and treatment of such addiction.