[The "tug of war" in healthcare: psychologists' conception and practice concerning Matrix-Based Support in the Center for Family Health Support].

The current study analyzed the conception and practice of matrix-based support among psychologists working at the Center for Family Health Support (NASF in Portuguese) in the city of São Paulo, Brazil. A qualitative methodology was used with semi-structured interviews that were taped, transcribed, and submitted to thematic content analysis. The study revealed dilemmas between the work as prescribed and what is possible to achieve in practice, and between idealization of the collaborative proposal and its implementation. Exchanges of knowledge and training appear as the principal meanings in the matrix-based concept. The practice revealed a complex context with heterogeneous work organization, lack of linkage between management levels and tensions in the execution of shared work, such as unequal division of tasks, in with the family health teams take responsibility for direct care to the population, while the NASF occupies the role of training and supervising, thereby generating conflicts over responsibility for care and creating a context which is hardly conducive to comprehensive, shared, and collaborative care.