[Addiction: a disease like no other?].

Addiction is undoubtedly a prototypical complex disorder owing to its multidimensional characteristics: socio-political, environmental, behavioral and cognitive, cellular-molecular, and perhaps genetic. At least four main questions are now open to debate: 1. the definition (what is drug dependence) posits that at the core of the syndrome three constructs must be considered: compulsive use, loss of control and a spiralling affective negative state, suggesting that complex neuropsychological-cognitive and emotional processes are involved; 2. there are huge individual differences concerning vulnerability to drugs and finally few subjects using drugs in a recreational way will succomb, a fact not reflected in the animal model; 3. at the neurospsychiatric level many brain regions, as well as hormonal systems, are functionally intricated, well beyond the classical dopamine-reward system; 4. the neurobiological adaptation that occurs in the course of dependence is often labelled as sensitization, which constitutes an oversimplification.