Choline in tardive dyskinesia and Huntington's disease.

Eight men, 4 with tardive dyskinesia and 4 with Huntington's disease, were treated with oral doses of choline chloride up to 20 g daily for three to eight weeks. Prior to treatment, 7 of the 8 patients were tested with a graded dose of 3 mg of physostigmine salicylate, a cholinesterase inhibitor. Six of these 7 patients had a favorable acute response to physostigmine. The same six patients had a favorable response to chronic treatment with choline chloride. Relapses following a switch from active treatment to placebo were delayed, but this could not be explained on the basis of the rate of choline disappearance from plasma. Re-treatment with choline chloride reversed relapse in most instances. Choline chloride may ameliorate these movement disorders by increasing central cholinergic activity, but other mechanisms are possible. Its practical importance as a treatment needs further elucidation.