2026 ECNP Congress

PS01-1212

Twenty-year trajectories of individual negative symptoms following first hospitalisation for schizophrenia

Dawid Kruk — A. Cechnicki · Jagiellonian University Medical College, Doctoral School of Medical and Health Sciences, Cracow, Poland

2026 ECNP Congress

Introduction. Negative symptoms are among the most disabling features of schizophrenia, strongly affecting long-term functioning and quality of life [1]. Short-term studies demonstrate improvement after the first psychotic episode, yet long-term findings are inconsistent: some indicate stabilisation, while others reveal U-shaped trajectories with late-phase deterioration [2, 3]. Most longitudinal studies analyse only aggregate scores rather than individual domains. Given that individual negative symptom domains have distinct neural correlates [4] and may have different therapeutic implications [1], modelling their separate trajectories is essential for personalising treatment.

Aim. To investigate whether three negative symptoms — motor retardation, emotional withdrawal, and blunted affect — display different twenty-year trajectories following first hospitalisation for schizophrenia.

Methods. Data were drawn from the Kraków Prospective Study of Schizophrenia, a twenty-year longitudinal cohort of 80 consecutively admitted patients (57.5% female) with first-episode schizophrenia. Symptom severity was assessed using the Brief Psychiatric Rating Scale Expanded version (BPRS-E) at six time points: admission and 1, 3, 7, 12, and 20 years post-discharge. Retention was 80.0% at year 20. Three BPRS-E negative symptom items — blunted affect, emotional withdrawal, and motor retardation — were modelled as ordinal outcomes. A Bayesian cumulative ordinal multilevel model was fitted jointly for all three symptoms, with fixed effects for symptom type, time (linear and quadratic terms), and centred baseline severity, and random intercepts and slopes. Prior specification, convergence diagnostics, and sensitivity analyses followed the WAMBS checklist [5]. Inference was based on posterior medians, 95% credible intervals (CrI), and Bayes factors (BF).

Results. All three symptoms displayed U-shaped trajectories: early improvement from admission to year 3, stabilisation between years 3 and 12, and late-phase deterioration thereafter. By year 20, mean severity returned toward baseline values (blunted affect: 2.96→2.28; emotional withdrawal: 2.84→2.22; motor retardation: 2.05→2.00). Motor retardation was less severe at baseline than emotional withdrawal (β = −0.85; 95% CrI [−1.31; −0.39]; BF₁₀ = 148) and blunted affect (β = −0.99; 95% CrI [−1.47; −0.52]; BF₁₀ = 223), with extreme evidence. No baseline difference between blunted affect and emotional withdrawal was found (BF₀₁ = 3.70). Weak evidence suggested motor retardation may be more persistent than emotional withdrawal (β = 0.25; 95% CrI [0.04; 0.45]; BF₁₀ = 2.84). No trajectory shape differences emerged between symptoms. Sensitivity analyses confirmed robustness of the baseline severity findings.

Conclusions. All three negative symptom dimensions follow similar U-shaped trajectories over two decades, with late deterioration returning symptoms toward baseline levels. The lower initial severity but potentially greater persistence of motor retardation suggests this symptom may follow a more trait-like course, possibly reflecting distinct neurodevelopmental underpinnings. These findings highlight the need for sustained monitoring and innovative interventions aimed at maintaining early gains rather than focusing solely on acute-phase symptom reduction. However, the BPRS-E does not cover the current five-domain consensus model of negative symptoms [1]; replication with second-generation instruments is warranted.

References

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