This article offers a comprehensive critical review of the most popular theoretical accounts on the recent processes of deinstitutionalization and reform of mental health services and their possible underlying factors, focusing in the sharp contrast between the straightforward ideas and models maintained by mainstream psychiatry and the different interpretations delivered by authors coming from the social sciences or applying conceptual tools stemming from diverse social theories. Since all these appraisals tend to illuminate only some aspects of the process while obscuring others, or do not fit at all with some important points of the actual changes, it is concluded that the quest for an adequate explanation is far from having been completed. Finally, some methodological and conceptual strategies for a renewed theoretical understanding of these significant transformations are also briefly discussed, including a comprehensive empirical evaluation of the facts, the consideration of the shifting social values and needs involved in mental health care provision and the historical analysis of deinstitutionalization policies within the framework of the broader social and cultural trends of the decades following World War II.