Neuroleptic malignant syndrome: life-threatening complication of neuroleptic treatment in adolescents with affective disorder. Neuroleptic malignant syndrome (NMS) is an uncommon, potentially fatal side effect of neuroleptic treatment characterized by hyperthermia, rigidity, rhabdomyolysis, and delirium. In recent clinical studies of adults it was suggested that affective disorder is a risk factor for the development of neuroleptic malignant syndrome. The cases of two adolescents with neuroleptic malignant syndrome who were treated with neuroleptic therapy because of psychotic symptoms in association with primary affective disorders are reported. The occurrence of these cases, as well as the observations in adults, suggests that attention to the primary psychiatric diagnosis is important in neuroleptic usage and that physicians should be vigilant to the occurrence of neuroleptic malignant syndrome in the pediatric population. 