The effect of duration of untreated psychosis (DUP) on the risk for hospitalization after admission to a first episode service.

Engagement with a first episode-psychosis service (FES) reduces the risk of psychiatric hospitalization. However, the role of the duration of untreated psychosis (DUP) in impacting this outcome is disputed. This study aimed to examine whether DUP was an effect modifier of the post-FES reduction of risk of hospitalization, and to explore associations between patients' characteristics and hospitalization post-FES. Individuals aged 16-35 with recent onset (< 3 years) of non-affective psychosis, admitted to the Program for Specialized Treatment Early in Psychosis (STEP), a FES serving the Greater New Haven area, Connecticut, between 2014 and 2019 were included (N = 189). Medical records were queried from 2013 through 2020 for number and duration of psychiatric hospitalizations. Poisson regression models were used to estimate incidence rate ratios for hospitalization rates across all explanatory variables. Negative binomial regression was used to compare the length of stay (LOS) before vs after STEP enrollment. STEP admission was associated with a significant 90 % reduction in the frequency and duration of hospitalizations. This effect was moderated by DUP: with 30-day prolongations in components of DUP (supply, demand, and total) there was less reduction in hospitalizations and LOS after FES enrollment (p < .0001). Only DUP supply (time from first antipsychotic use to STEP admission) differentiated those who were hospitalized during the first year after STEP enrollment from those who were not (median: 35 vs. 15 weeks, p = .003). To fully harness the positive impact of FES on hospitalization, a detailed effort should be pursued to reduce all DUP components.