Prospective relationship between duration of untreated psychosis and 13-year clinical outcome: a first-episode psychosis study.

Abstract Background The adverse effects of a long duration of untreated psychosis (DUP) have been explored in numerous short-term studies. These studies support the development of early interventions that reduce treatment delay and promote recovery. However, the enduring impact of DUP is largely unknown, partly due to the paucity of prospective long-term studies. Although the DUP–outcome relationship is commonly assumed to be linear, the threshold effect has not been adequately examined. Objective To explore the relationship between DUP and long-term symptomatic remission. Methods This was a prospective study of a cohort of 153 first-episode psychosis patients in Hong Kong at the 13-year follow-up. The patients were categorized into short (≤ 30 days), medium (31–180 days) and long (> 180 days) DUP groups. Results The long-term outcome was ascertained in 73% of the patients. Nearly half of the patients (47%) fulfilled the criteria for symptomatic remission. The short DUP group experienced a significantly higher remission rate over the course of the illness. The odds of long-term symptomatic remission was significantly reduced in the medium DUP (by 89%) and long DUP (by 85%) groups compared with the short DUP group. Further analysis showed that DUP had a specific impact on negative symptom remission. Conclusion The findings support the threshold theory that DUP longer than 30 days adversely impacts the long-term outcome. The present study is one of the few studies that confirmed the enduring impact of DUP on long-term outcomes based on well-defined criteria and adequate statistical adjustment.