Medical workup in pediatric first psychotic presentation: real-world diagnostic utility in a large tertiary cohort.

The medical evaluation of children and adolescents with first psychotic presentation aims to identify potentially reversible underlying medical conditions. However, recommendations regarding the extent of diagnostic investigations remain inconsistent. This study evaluated the diagnostic yield of the medical workup performed in children and adolescents presenting with first psychotic presentation at a tertiary medical center. We conducted a retrospective cohort study using electronic medical records from Soroka University Medical Center, Israel. All patients aged 5-18 years who presented to the pediatric emergency department or were admitted with a first-time diagnosis of psychosis between 2008 and 2023 were included (n = 235). Clinical, laboratory, neuroimaging, and electroencephalographic findings were reviewed to determine the diagnostic yield of each investigation. The cohort had a high prevalence of pre-existing neurodevelopmental and medical comorbidities. Urine toxicology identified substance-related findings in 19 patients (8.1%), predominantly cannabinoids. Routine laboratory investigations did not otherwise identify an underlying medical etiology. Two patients had corticosteroid-induced psychosis. Neuroimaging (77%) identified clinically explanatory findings in three patients (1.3%), all of whom had neurological abnormalities or atypical clinical features. EEG (48%) did not identify the etiology of psychosis in any case. In children and adolescents with first psychotic presentation, the medical evaluation should be guided by clinical findings and toxicology screening rather than routine extensive testing. Neuroimaging and electroencephalography rarely identify an underlying medical cause in the absence of neurological abnormalities or atypical clinical features, supporting a selective, clinically guided diagnostic approach.