Lithium-specific pathological electroencephalographic changes: a successful replication of earlier investigative results.

In three independent comparisons, patients treated with lithium carbonate (either alone or in combination with other agents) were contrasted with both medication free and other psychotropic medicated patients, in terms of the prevalence of abnormal generalized slowing and paroxysmal diffuse delta activity in the clinical EEG. In all samples, abnormal EEG changes occurred in from 30.3 to 39.4% of lithium treated patients as contrasted with from only 1.5 to 4.6% of medication free controls. In all comparisons, the prevalence of abnormal EEGs was significantly higher for lithium treated patients than for patients free of medication or those treated with other psychotropic agents. EEG changes are reversible with discontinuance of lithium, and their role in suggesting potential early neurotoxicity is discussed.