The Effects of Lithium on Electroencephalogram, Behavior and Serum Electrolytes

The effect of acute and chronic administration of lithium carbonate on electroencephalogram (EEG), behavior and serum electrolytes was studied in 10 patients. Five patients, 3 of whom are manic-depressive in the manic phase, and 2 who were schizo-affective in the excited phase, received lithium as part of a double blind, controlled evaluation of lithium and chlorpromazine in manic states. The remaining 5 were patient volunteers in a study of the effect of lithium on electrolyte metabolism. EEG studies were carried out using a 16-channel model 6B electroencephalograph and, in addition, the data were placed on magnetic tape using an Ampex FR-1200, 14-channel tape recorder. Eight channels of the EEG were taped, and other channels included photic stimuli, finger movements and time code for identification of epochs. Photic stimuli in both random and one per second sequences were used to determine average evoked response and reaction time. A base line EEG was followed by ingestion of 750 mg of lithium carbonate, and after 11/2 hours an acute postdrug EEG was repeated and blood was drawn for serum lithium and electrolyte analyses. A third record was taken after chronic administration of lithium. Acute lithium administration produced only minimal EEG changes without the presence of behavioral change. Transient fluctuations in serum electrolytes were observed. Following chronic administration, the presence and severity of the EEG changes were most highly correlated with neurotoxicity. EEG changes observed included alterations in the alpha activity, diffuse slowing, accentuation of focal abnormality and changes in average evoked response. Although there was some relationship between serum lithium levels and EEG changes, patient-specific variations, cerebral organic disease and, possibly, sodium balance are important variables. Clinical psychiatric change was not related to EEG changes. The problem of drug-specific EEG changes and possible modes of action of lithium were discussed.