Iron deficiency in pediatric patients in long-term risperidone treatment.

Objective: Atypical antipsychotics, increasingly used in children and adolescents, modulate brain dopamine. Iron plays a critical role in dopaminergic signaling. Therefore, we explored whether body iron status is related to psychiatric symptom severity, treatment response, and tolerability following extended antipsychotic therapy.

Methods: Between November 2005 and August 2009, medically healthy 7-17-year-old risperidone-treated participants enrolled in a cross-sectional study examining the long-term safety of this antipsychotic. Anthropometric measurements were obtained. Psychiatric symptom severity and dietary intake were assessed. Serum ferritin, transferrin receptor, and prolactin concentrations were measured. Linear multivariable regression analysis tested the association among body iron, symptom severity, the dose of risperidone and psychostimulants, and serum prolactin concentration.

Results: The sample consisted of 115 patients (87% males) with a mean (±SD) age of 11.6 (±2.8) years. The majority had externalizing disorders, and they had taken risperidone for 2.4 (±1.7) years. Body iron was low, with 45% having iron depletion and 14% having iron deficiency. Iron status was inversely associated with weight gain during risperidone treatment and with interleukin-6. Body iron was neither associated with psychiatric symptom severity nor with the daily dose of risperidone and psychostimulants. It was, however, inversely associated with prolactin concentration, which was nearly 50% higher in the iron-deficient group.

Conclusions: Iron depletion and deficiency are prevalent in children and adolescents chronically treated with risperidone. Iron deficiency accentuates the antipsychotic-induced elevation in prolactin. Future studies should confirm this finding and investigate the potential benefit of iron supplementation in antipsychotic-treated patients.