Schizo-affective psychosis: definitions and incidence.

Eight definitions of schizo-affective psychosis have been compared in a sample of psychotic first admissions. Their mutual concordance is very low (mean 0.19) showing that there is very poor agreement about the meaning of the term 'schizo-affective' at present. Ten patients (4.5% of admissions and 8% of psychotic admissions within the age group studied) satisfied 3 definitions, a figure which demonstrates the numerical importance of this group of unclassified mental disorders.