Lithium-neuroleptic neurotoxicity in the elderly bipolar patient.

The frequency and clinical characteristics of lithium- and neuroleptic-mediated neurotoxicity were determined in 10 elderly bipolar patients. When lithium was used alone and therapeutic serum lithium levels were achieved, neurotoxicity did not develop. However, when a neuroleptic was added, neurotoxicity developed in 60% (three of five) of patients and was characterized by delirium, extrapyramidal signs, and cerebellar dysfunction. Neurotoxicity occurred despite the use of neuroleptic dosages that are considered safe and useful when administered in the absence of other psychoactive drugs.