Frequency of Diagnoses of Schizophrenia Versus Affective Disorders from 1944 to 1968

Frequencies of schizophrenic versus affective psychoses from 1944 to 1968 at a university psychiatric clinic revealed an abrupt increase in the rate of schizophrenic diagnoses at the start of the phenothiazine treatment era and a sharp increase in diagnoses of affective psychosis with the advent of lithiumn therapy. As one group of diagnoses increased, the other decreased. One responsible factor may be the introduction—in the setting of a complex differential diagnostic problem—of observer bias, modified by the availability of novel and effective therapies.