The effect of two predictors' interaction on short- and long-term treatment outcomes of schizophrenia

To monitor the effect of interaction of duration of untreated psychosis (DUP) and expressed emotion (EE) on treatment outcomes in schizophrenia. 56 individuals diagnosed with schizophrenia were assessed at 4 time points. The number of relapses, the number and duration of rehospitalizations and the severity of symptoms were assessed at index hospitalization and at 3, 7 and 12-year follow-ups. No correlation was found between DUP and EE measured at index hospitalization. Over the 12-year period the number of rehospitalizations for individuals with short DUP and low EE did not increase, as opposed to those with short DUP and with high EE. In the group with long DUP, the number of rehospitalizations increased irrespectively of EE level. The positive syndrome in the group with short DUP and high EE was less severe than in individuals with long DUP and high EE. Analogous differences appeared in the group with low EE. 1) No correlation was found between DUP and EE at index hospitalization. 2) Number of rehospitalizations and intensity of positive symptoms proved to be associated over time with the interaction of DUP and EE. 3) Long-time observation and multiple assessments allow to obtain more reliable results.