Manipulation of cerebral monoamines in the treatment of human epilepsy: a pilot study.

The effects of L-DOPA, L-tryptophan, monoamine oxidase inhibitor (MAOI), and MAOI plus L-tryptophan, each for 3 months, have been assessed in 10 severe, adult epileptics with placebo control. There was no overall reduction in seizure frequency, but 2 patients with minor partial seizures improved, 1 with L-DOPA, MAOI, and MAOI plus L-tryptophan, and the other with L-tryptophan and MAOI plus L-tryptophan. We have not been able to demonstrate an increased turnover of cerebral serotonin (5-HT), as measured by cerebrospinal fluid 5-hydroxyindoleacetic acid, after treatment with L-tryptophan for 3 months. This observation casts doubt on the ability of L-tryptophan to alter the long-term metabolism and functional activity of brain 5-HT. The importance of further exploration of manipulation of cerebral monoamines as a possible approach to the treatment of epilepsy is emphasized.