Myoclonus and ocular oscillations induced by L-tryptophan

A patient with chronic manic-depressive illness developed generalized myoclonus and spontaneous ocular oscillations after a single 2 gm dose of L-tryptophan. She had been pretreated with both a tricyclic antidepressant and a monoamine oxidase inhibitor. The involuntary movements gradually disappeared within 24 hours after the drugs were discontinued. Electrooculographic recording 7 hours after onset of the abnormal eye movements revealed square-wave jerks and hypometric voluntary saccades. Pursuit as well as optokinetic and vestibular slow phases were normal except for superimposition of the square-wave jerks. Repeat recording 24 hours later was entirely normal.