The treatment of so-called adult subjects is often punctuated with references to a period of time which they call their adolescence. We shall start from a postulate: the moment of adolescence could be defined as the time when the child fantasy is recast. The psychical work of the becoming-adult could then be grasped as the moment when this refashioned construction can be examined. The solidity of this construction could then be put to the test, or else its faults could be fathomed so as to attempt a new construction. We shall endeavour to illustrate this through various clinical cases.