Background: A number of studies have reported evidence of a relationship between longer duration of untreated psychosis (DUP) and poorer outcome at 1 year while others have failed to find such evidence. It is possible that several other predictors may confound this relationship and there may be different predictors for different dimensions of outcome. In the current study we examined relationship between DUP and several other predictors, and 1 year outcome on rate and level of remission as well as level of positive, negative, depressive and anxiety symptoms in a community cohort of first episode psychosis patients.
Method: All potential cases of a first episode of non-affective psychosis were assessed and offered treatment in a comprehensive treatment program. Data were collected on all patients who completed 1 year of treatment on a number of predictor variables (DUP, length of the prodromal period, age of onset, gender, pre-morbid adjustment during childhood and adolescence, diagnosis) and outcome variables (level of remission, positive, negative, depression and anxiety symptoms based on ratings on SAPS, SANS, CDS and HAS, respectively). Data were analysed using an analysis of variance, bivariate correlations and hierarchical regression analysis.
Results: Of a total of 130 patients were offered treatment, 106 completed 1 year of treatment and complete data were available on 88 subjects, 80% of whom met criteria for schizophrenia spectrum psychosis. The rate and level of remission were significantly higher for patients with shorter DUP (<22 weeks). DUP was the only independent predictor of the level of remission as well as reality distortion at 1 year; for disorganization syndrome and negative symptoms it was the age of onset and level of premorbid adjustment in adolescence, respectively; while the level of anxiety was predicted by the length of the prodrome. Additional predictors increased the variance explained by each model.
Conclusion: Our results confirmed the independent role of DUP in remission and positive symptom outcome at 1 year, thus providing support for the enthusiasm for early intervention. However, the model including DUP and premorbid adjustment in early adolescence explained a greater amount of variance in outcome on positive symptoms than DUP alone. On the other hand, outcome on negative symptoms, disorganization and anxiety are more likely to be influenced by longer term characteristics such as premorbid adjustment, earlier age of onset, gender and the length of the prodromal period, and therefore may not be as responsive to effects of early intervention.