RESUMEN
BACKGROUND: Treatment with the atypical antipsychotic risperidone can result in elevated prolactin levels. To date, the relationships between plasma concentrations of prolactin, risperidone and its active 9-hydroxy-metabolite have been little investigated in adolescents with psychosis. METHODS: Prolactin levels were determined at baseline in 16 hospitalized drug-naïve adolescents meeting DSM-IV criteria for schizophreniform disorder. Prolactin, risperidone, 9-hydroxyrisperidone levels were subsequently determined after 3 weeks of oral risperidone treatment. RESULTS: Compared with pretreatment values, prolactin levels at endpoint were significantly increased (p<0.00001) and correlated with risperidone doses (r=0.58, N=16, p<0.02), and plasma levels of risperidone (r=0.60, N=16, p<0.02) and 9-hydroxyrisperidone (r=0.54, N=16, p=0.03). CONCLUSIONS: These data suggest that risperidone's effect on prolactin release is dose-dependent in adolescents and is linked to both plasma risperidone and 9-hydroxyrisperidone concentrations.