Low melanin content of substantia nigra in a case of neuroleptic malignant syndrome.

A 19-year-old man suffering from a first episode of schizophrenia developed a neuroleptic malignant syndrome (NMS) after administration of haloperidol and levomepromazine. After five weeks of neuroleptic treatment he died of an unknown cause. Histological examination of the brain revealed a low melanin content in neurons in the substantia nigra (SN). Since neuromelanin in SN is the end-product of nonenzymatic dopamine degradation, the amount of melanin probably depends on the overall amount of dopamine produced during life. Thus, dopamine production must have been low in the reported case. In addition, ectopic neurons were found in subcortical white matter.