In a time when manic-depressive disease became bipolar disorder, and it is conceptualized and treated almost as a fully medical illness, such as epilepsy, we found worth returning to some psychodynamic aspects underlying this condition. Conventionally, we depart from the concept of melancholy, to introduce in a second time, the mania, as a liberating solution of the depression. To Abraham, mania is the liberation from suffering imposed by the reality principle For Freud, mania becomes a leak from the ego face a tyrannical superego (the encounter of ego and the ego ideal). Klein explains that the mania serves to counter the depressive position and thus avoid the guilt inside of ego. For Racamier, mania is clearly a frantic negation of the anguish and emotional suffering. Today, some authors as Chabot and Husain try to define the manic depression organization, with the help of projective tests. This personality structure would be between psychosis and borderline. An axial element of this structure is the research for an affective symbiosis with each other. These concept, strongly resemble the "syntony", from Bleuler. We trace the evolution of manic depression from a psychodynamic and structural point of view, with particular interesting in the concept of syntony.