This article summarizes the main discussions at a meeting on the biolo
gical, social and clinical bases of drug addiction focused on contempo
rary topics in drug dependence. Four main domains are surveyed, reflec
ting the structure of the meeting: psychological and pharmacological f
actors; neurobiological substrates; risk factors (including a consider
ation of vulnerability from an environmental and genetic perspective);
and clinical treatment. Among the topics discussed were tolerance, se
nsitization, withdrawal, craving and relapse; mechanisms of reinforcin
g actions of drugs at the behavioural, cognitive and neural levels; th
e role of subjective factors in drug dependence; approaches to the beh
avioural and molecular genetics of drug dependence; the use of functio
nal neuroimaging; pharmaceutical and psychosocial strategies for treat
ment; epidemiological and sociological aspects of drug dependence. The
survey takes into account the considerable disagreements and controve
rsies arising from the discussions, but also reaches a degree of conse
nsus in certain areas.