Difference of Symptoms Networks in Early and Late Phase Schizophrenia; A Cross-Sectional Network Analysis

The functional remission or recovery of schizophrenia patients is a challenging task which relies on pharmacotherapy but also on the timing of psychotherapy and other therapeutic interventions. The study aimed to assess the difference in strength and structure of symptoms networks between early and late phase schizophrenia. Our secondary objective was to check whether the overall, positive, negative, and general symptoms severity change over the course of treatment and disorder.

This nested cross-sectional analysis combined the samples from two studies performed during 2014-2016 at University Psychiatric Hospital Vrapče, Zagreb, Croatia on the consecutive sample of men 30-60 years old diagnosed with schizophrenia, 85 of them in the early (≤5 years from diagnosis), and 143 in the late phase of the illness. The study was funded by the project: "Biomarkers in schizophrenia - integration of complementary methods in longitudinal follow up of FEP patients".

Median (IQR) age of the participant in the early phase was 36 (32-45) years and in the late phase 44 (38-49) years. Patients in the early phase had significantly higher odds for being in the symptomatic remission compared to the patients in the late-phase schizophrenia (OR=2.11; 95% CI 1.09-4.09) and had 10% less pronounced negative symptoms. The global strength, density, and structure of the symptoms network were not significantly different between the two study groups.

Negative symptoms severity change with the course of illness and differ from the early to the late phase of schizophrenia. However, the overall network of psychotic symptoms is relatively stable, and overall strengths or density and the partial relationship between particular symptoms do not change significantly. The observed worsening of negative symptoms is probably at least partially caused by the lack of clear guidelines and effective treatment options aimed specifically toward negative symptoms.