Objectives:
Schizophrenia spectrum disorders (SSDs) in children and adolescents are rare but clinically severe conditions. In Poland, evidence regarding diagnostic practices and system-level determinants of pediatric SSD diagnoses remains limited. This study aimed to analyze nationwide trends in first-time inpatient diagnoses of SSDs in youth between 2014 and 2019, with a focus on age distribution, diagnostic coding patterns (F20, F21, F25), and selected indicators of service utilization and reimbursement.

Methods:
A retrospective register-based analysis was conducted using national inpatient data from the Polish National Health Fund (NFZ) for the years 2014–2019. The study included 9,034 patients aged 0–17 years who received a first-time diagnosis of SSDs coded as F20, F21, or F25 according to ICD-10. Trends in age at diagnosis, diagnostic category distribution, hospitalization volume, and reimbursement indicators were analyzed descriptively over time.

Results:
Between 2014 and 2019, 9,034 inpatients aged 0–17 years received first-time SSD diagnoses. Schizophrenia (F20) overwhelmingly predominated across all age groups, while F21 and F25 were rarely used. A shift toward younger adolescents was observed, with a growing proportion of diagnoses in the 13–14-year-old age group and a gradual decline among patients aged 15–17 years. Hospitalization numbers remained relatively stable, while the volume of reimbursed services declined and total refunds increased, suggesting rising per-case costs despite lower service utilization.

Conclusions:
The findings indicate a shift toward earlier diagnostic labeling of schizo- phrenia spectrum disorders in Polish youth and a marked overreliance on the F20 code, suggesting diagnostic oversimplification. These patterns are likely influenced by systemic and reimbursement-related factors and by the limited developmental sensitivity of the ICD-10 classification, particularly in pediatric psychiatry. Comparable coding tendencies and age-distribution shifts have been reported in U.S., German, and Scandinavian register-based studies, indicating that the Polish findings reflect administrative and structural influences on diagnostic practice rather than true epidemiological differences. Adoption of developmentally informed classification principles, such as those embodied in DSM-5, may improve diagnostic accuracy, care planning, and resource allocation in child and adolescent psychiatry.