Antistreptolysin O Titers, Symptom Burden, and Multidimensional Correlates in Children with Suspected Streptococcal-Associated Neuropsychiatric Presentations: A Cross-Sectional Observational Study in a Clinically Referred Cohort

Pediatric acute-onset neuropsychiatric presentations occurring in the context of prior streptococcal exposure remain clinically important but diagnostically inconclusive, particularly at the interface between Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) and Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections (PANDAS). This cross-sectional observational study examined whether serological, psychometric, and electroencephalographic findings converged within a clinically referred pediatric psychiatric cohort at the index assessment. Children and adolescents evaluated for neuropsychiatric symptoms in the context of caregiver- or record-supported history suggestive of prior streptococcal exposure were recruited over a 12-month period through inpatient and outpatient child psychiatric services. Out of 154 screened cases, 96 with analyzable index assessment data were retained and stratified by antistreptolysin O (ASO) status. Symptom burden was quantified using the Pediatric Acute-onset Neuropsychiatric Syndrome 31-Item Symptom Rating Scale (PANS-31) which was treated primarily as a continuous dimensional outcome and examined in relation to ASO titers, time since the last reported streptococcal infection, electroencephalography (EEG) findings, and selected developmental and clinical-history variables. Higher ASO values were associated with greater PANS-31 symptom burden, whereas a shorter interval since the last reported streptococcal infection was associated with both higher ASO titers and higher symptom scores. PANS-31 showed good total scale internal consistency and meaningful domain-level convergence with age-appropriate Child Symptom Inventory-4 (CSI-4) and Adolescent Symptom Inventory-4 (ASI-4) domains. Exploratory within-cohort stratification using an operational PANS-31 threshold and alternative post hoc thresholds suggested that higher symptom burden subgroups were largely confined to the ASO-positive stratum; however, these threshold-based patterns were interpreted descriptively and not as diagnostic performance or predictive classification. These findings do not support a disease-specific biomarker model, but suggest that higher anti-streptococcal serology, more recent streptococcal exposure, and greater neuropsychiatric burden may cluster as a clinically interpretable association pattern in a selected real-world psychiatric sample.