LA JOLLA, CALIF. — Children and adults with chronic tic disorders who were treated with levodopa did not experience a worsening of tics, Dr. Mollie Gordon reported during a poster session at the annual meeting of the American Neuropsychiatric Association.
Treated patients did experience significant improvements in attention and hyperactivity symptoms.
“I think this challenges the way we think about the dopamine pathways in the brain,” Dr. Gordon, of the department of psychiatry at Washington University School of Medicine, St. Louis, said in an interview. “We've always thought of Tourette as being in a sense an excess of and when we block the dopamine, these patients do better.” But their tics do not worsen when given exogenous dopamine. In an 8-week pilot study, Dr. Gordon and her associates randomly assigned 12 children and 18 adults with Tourette syndrome or chronic tic disorder to receive 12.5 mg of carbidopa, 50 mg of levodopa, or matched placebo capsules.
The researchers found that tic severity did not increase in patients who took levodopa; instead levodopa improved attention and hyperreactivity symptoms (a 17% improvement vs. no improvement for those on placebo), and the drug was not associated with any significant side effects.
“We know that these patients have a dopamine abnormality in the brain,” Dr. Gordon said. “If it's not a matter of being too much or too little [dopamine], the question is, how do we figure out what's wrong? Is it a dopamine dysregulation? Do these drugs affect auto inhibitory receptors? Is there something going on in the brain that has to do with the dopamine dysregulation? If we [have] more information about the pathophysiology of these diseases, then we can figure out the best management.” The study was funded in part by the Tourette Syndrome Association.