Longer untreated psychosis linked to less symptom improvement in first-episode schizophrenia

BackgroundSchizophrenia is a severe mental disorder associated with substantial disability. Although a growing body of evidence suggests that the duration of untreated psychosis (DUP) may influence prognosis, findings remains inconsistent.MethodsWe retrospectively analyzed 99 first-episode schizophrenia patients hospitalized at Shantou University Mental Health Center between 2015 and 2019. DUP was categorized as short (≤26 weeks) or long (>26 weeks). Symptom improvement was assessed as changes in Brief Psychiatric Rating Scale (BPRS) score from admission to discharge. Propensity score matching was used to improve baseline comparability between DUP groups. A Bayesian linear regression model was then fitted to evaluate the adjusted association between DUP and BPRS improvement. Subgroup analyses were performed to assess whether the association varied across clinical characteristics.ResultsIn the unmatched cohort, patients with short DUP showed greater BPRS improvement than those with long DUP (mean difference 7.23 points, 95% CI 2.92 to 11.53). After matching, 22 pairs of patients were retained, and the association remained evident, with a larger improvement in the short DUP group (mean difference 11.50 points, 95% CI 5.92 to 17.08; P < 0.001). In the adjusted Bayesian model, long DUP remained associated with less symptom improvement (posterior median β = -3.93, 95% CrI -6.93 to -0.91, pd = 0.994), whereas higher baseline BPRS score was associated with greater improvement (posterior median β = 0.66, 95% CrI 0.55 to 0.77). Subgroup analyses suggested that the adverse association of long DUP was more pronounced among patients with higher baseline symptom severity (interaction P = 0.014).ConclusionsShorter DUP was associated with greater symptom improvement in hospitalized patients with first-episode schizophrenia, which remained after matching and covariate adjustment and appeared stronger among patients with higher baseline symptom severity. These findings support DUP as a clinically useful prognostic indicator and reinforce the importance of earlier detection and timely intervention in first-episode schizophrenia.