Lithium carbonate and brain function. I. Cerebral-evoked potentials, EEG, and symptom changes during lithium carbonate treatment.

Eighteen patients were studied with behavioral ratings and the somatosensory (SER), auditory (AER), and visual (VER) cerebral-evoked response and quantified EEG before and during lithium carbonate treatment. The amplitude of early positive SER components and most AER components increased during treatment, but VER did not change. The intensity of EEG delta and theta frequencies increased, and the dominant alpha frequency slowed. Before treatment, there were few significant correlations to symptom intensity. Patients with an increase in symptoms on treatment had the greatest increase in EEG delta intensity and the dominant alpha frequency slowed in patients who became more depressed. The EEG slowing in patients with a normal sensorium and the change in cerebral cortical activity after transmission in the somatosensory pathway over just three synapses demonstrate a unique and specific effect of lithium carbonate on brain function.