The elusive nature of the social practice called neuropsychiatry is the most important obstacle for writing its history. At different times, and in different countries, the term has been used to name different ideological and professional packages. Choosing any of these as the prototype would, however, bias and regionalize the historical account. One solution is to identify an ideological marker or common denominator. To spin its yarn, this paper has chosen the foundational claim (putatively common to all practitioners of 'neuropsychiatry') that all 'mental disorders are disorders of the brain'. Three among its results are worth noting. One is that the meaning and exercise of 'neuropsychiatry' will continue to depend on social, economic and political factors; this augurs future instability. The second is that each time that the foundational claim has been uttered in history it has meant something different. Further research is needed to clarify whether this is due to the way in which the claim becomes 'inscribed' in different cultural niches; what is clear is that by using the foundational claim as a marker it is not possible to establish a continuity in the progress of neuropsychiatry. The third finding is that users of the foundational claim require the use of a concept of matter and in this paper 'plain' and 'baroque' types of matter have been identified. To explain the origin of mind, those using the plain notion need to resort to external ingredients and their narratives incorporate bits of the real world. Users of the baroque definition do not need such aids. It is not for the historian to judge which of these two definitions is more felicitous and more conducive to the moral and aesthetic edification of psychiatry and her patients.