The safety of lithium carbonate, now in widespread use for treatment of manic-depressive disorders, has been questioned because of reports that it lowers the seizure threshold in patients prone to convulsive disorders.
Seventeen state hospital patients were studied. Fifteen were severe epileptics, poorly controlled clinically with standard anticonvulsants and one had been well controlled; one patient had an abnormal electroencephalogram with no clinical history of seizure activity. All were administered lithium carbonate for a six-week period. EEGs were obtained prior to the study and twice weekly during the study. Serum lithium ion levels were determined prior to each EEG during the study period and maintained between 0.6 and 1.25 mEq/liter.
There was only one instance of increased clinical seizure activity, while ten of the 16 seizure patients showed a clear reduction of seizure frequency. EEG changes paralleled clinical findings with one exception. Status epilepticus was not encountered and only one patient had more seizures (4.0/mo) during the lithium carbonate treatment period than during the baseline period (1.8/mo).