The deficit syndrome of schizophrenia: towards heterogeneity.

Since the turn of the century, psychiatrists have been concerned with both the unity and diversity of schizophrenia. From these early descriptions until now, many authors have attempted to delineate clinically meaningful subtypes within this disorder. In this connection, negative/positive subtyping has generated great interest. Carpenter and his team have emphasized the origin of the negative symptoms observed. They have proposed that primary enduring negative symptoms should be distinguished from transient negative symptoms resulting from treatment, depression or social deprivation and should be termed deficit symptoms. The validity of this subtyping is supported by clinical, biochemical or electrophysiological studies showing differences between deficit and nondeficit patients.