Case report: Effective treatment of posttraumatic aggression in a child affected by TBI treated with long-acting injectable paliperidone: a case study and literature review

Post-traumatic confusional state (PTCS) is a disabling sequel of pediatric traumatic brain injury (TBI), with little guidance on pharmacologic management when aggression and poor impulse control dominate and adherence is poor. We describe a 9-year-old boy with severe TBI who evolved from coma to a prolonged PTCS characterized by agitation, externalizing behaviors, and dysexecutive symptoms. Multiple oral agents-risperidone, methylphenidate, olanzapine, and aripiprazole-were trialed over several years with minimal benefit and poor adherence. Following an acute agitation episode in 2022, long-acting injectable (LAI) paliperidone palmitate was initiated (100 mg then 150 mg monthly) with adjunct nightly risperidone 2 mg. Over two years, aggression markedly decreased and functional status improved from Rancho Los Amigos Level IV ("confused-agitated") to Level VIII ("purposeful-appropriate"). Cognitive testing at age 19 showed average intellectual ability but persistent executive dysfunction. Adverse effects were limited to weight gain and asymptomatic hyperprolactinemia; no extrapyramidal or cardiac events occurred. While spontaneous recovery and developmental maturation cannot be excluded, this case suggests LAI paliperidone can be a practical option to stabilize severe PTCS-related behavioral dysregulation when oral adherence fails. Larger, controlled studies are needed to clarify efficacy, safety, and long-term neurocognitive impact of LAI antipsychotics in pediatric TBI.