We compared the prodromal symptoms of patients who had sought help at an early detection center; had been assessed at baseline with the Structured Interview for Prodromal Syndromes (SIPS); and who, within 53 months on average, developed schizophrenia-spectrum psychosis (pre-SCZ; n = 51), affective disorder with psychotic features (pre-AD-P; n = 7), or affective disorder without psychotic features (pre-AD-noP; n = 16).
While pre-SCZ scored slightly higher on most positive symptoms than pre-AD, pre-AD-P and pre-SCZ scored comparably across the SIPS; moreover, pre-AD-noP and pre-SCZ differed on most subscales and items, particularly on the positive and negative dimensions. Furthermore, pre-AD-P scored higher on positive symptoms than pre-AD-noP.
Our results suggest that, in the early detection of affective disorders, those that might take on a psychotic form and those with a non-psychotic course need to be considered separately. While the current at-risk criteria for psychosis function well in detecting those with a psychotic course, those with a non-psychotic course would benefit from the development and evaluation of new at-risk criteria and new early detection instruments.