A sample of pre-1967 case records with a hospital diagnosis of schizoaffective disorder were presented for rediagnosis to members of the present staff of the Institute of Psychiatry/Maudsley Hospital. The raters were asked to make a diagnostic choice of either schizophrenia or schizoaffective disorder or affective disorder and indicate how useful they would consider certain treatments for the present episode and for the long term. There was a significant trend in diagnosis to affective disorder but this trend was not correlated with the usefulness of certain treatments, e.g. lithium, a drug which had not been in use before 1967.