The effects of clozapine on positive and negative symptoms were studie
d in 103 patients with treatment-refractory schizophrenia. The evaluat
ion of symptom profile was made before and after clozapine treatment.
Overt psychopathology did not vary significantly before clozapine trea
tment. Significant decreases in positive and negative symptoms were no
ted by the third month on clozapine. No further significant progress c
ould be observed after 6 months of treatment. No fatal cases were obse
rved, although two patients developed agranulocytosis during clozapine
treatment.