The concept of ordalic behaviour, as a bridge across several disciplines in the field,of human sciences, is from its origins inscribed within a continuity of a descriptive, clinical, phenomenological approach of toxicomania. Not offering any explicative pattern, it yet offers a new angle liable to cast a light, and bee applied onto several kinds of high risk behaviours with adolescents. A pattern for addictions (in both the current and North-American broader sense of the word) may however be sketched while taking into account the opposition between two facets of such behaviours : on the one hand, dependency as loss of meaning, sometimes even a desubjectivazion, on the other, ordalic behaviour as an ultimate quest for a new meaning within the closeness of risk of dying in the same way as transgression may be a quest for limits.