Response to levodopa challenge in Tourette syndrome

A dopaminergic excess has been commonly postulated in the pathophysiology o f ties, and an early report described acute worsening of ties with levodopa . However, dopamine agonists sometimes improve ties. We undertook this pilo t study to determine whether people with ties could tolerate an acute dose of levodopa. Six adults with Tourette syndrome (TS) who had never been trea ted with neuroleptics took 150 mg levodopa by mouth under single-blind cond itions after carbidopa pretreatment. All six subjects reported a decrease i n self-rated tic severity (mean -40%, p <0.05), and three spontaneously ask ed if they could be prescribed levodopa for chronic treatment. Blinded vide otape ratings of motor tic severity improved by 37% (p <0.02). A large, pla cebo-controlled trial will be required to confirm these findings, which rai se important questions concerning the relationship of tie expression to dop aminergic activity.