Plasma microRNA signatures in drug-naïve Romanian adolescents with first-episode psychosis

Psychotic disorders are a group of severe psychiatric conditions with onset typically occurring in adolescence or early adulthood. Despite significant efforts to identify clinically useful candidates, no validated biomarkers for psychiatric disorders currently exist. The diagnosis of psychotic disorders is exclusively based on clinical assessment, significantly affected by individual differences and symptom overlap. Although circulating microRNAs (miRNAs) have emerged as potential peripheral biomarkers for early diagnosis and disease evolution, most studies concentrate on adult, medicated cohorts. Studies on miRNA profiles in drug-naïve adolescents with first-episode psychosis (FEP) are scarce. This study aims to identify the plasma miRNA profile in treatment-naïve Romanian adolescents with first-episode psychosis and to compare it with that of age- and sex-matched healthy controls. The plasma from 14 adolescents, seven drug-naïve FEP and seven and age-matched controls (CTRL) aged 15-18 years was collected. Psychiatric symptoms were assessed using PANSS, HAM-D, and YMRS scales. The levels of 179 miRNAs were assessed using qRT-PCR. A case-control analysis on miRNAs levels between FEP and CTRL was performed, as well as correlations with clinical measures. Twenty-one miRNAs showed significantly lower levels and two higher levels in FEP patients compared to controls. After adjustment for multiple comparisons, miR-125a-5p, miR-205-5p, miR-145-5p, miR-363-3p, and miR-23b-3p remained statistically significant (FDR<0.05). Notably, miR-125a-5p, miR-23b-3p, and miR-146a-5p levels negatively correlated with psychotic, depressive, and manic symptom severity, while miR-16-5p and miR-363-3p positively correlated with symptom scores. Comparison with previous studies indicated limited overlap, reflecting potential influences of age, treatment status, and genetic or environmental factors. This work demonstrates that Romanian treatment-naïve adolescents with first-episode psychosis had a unique circulating miRNA profile correlated with symptom severity, indicating their potential as early-stage biomarkers. The results underscore the necessity of accounting for age, treatment status, and environmental variables in the interpretation of miRNA modifications in psychotic illnesses.