nstead emphasized that splitting of psychic functioning is an essential feature of this disorder. One of the main differences between Kraepelin and Bleuler viewpoints is that the Kraepelin studies of SCHZ were retrospectively, using medical records whereas Bleuler's studies were prospective, involving a

ion. Unlike Reynolds, Jackson believed that positive and negative symptoms were different manifestations of a single process. Kraepelin (1919) and Bleuler (1908) adopted Jackson's theory of positive and negative symptoms in their conceptualizations of schizophre- nia. A shared aetiopathophysiology for