Though it has been known for more than a century, the neuropsychiatric disorder Tourette's syndrome (TS) remains difficult to treat. But findings from two clinical trials described in this month's issue of the journal Neurology may help point the way to new therapies.
In the first study, Johns Hopkins University neurologist Harvey Singer and his colleagues found that the drug baclofena muscle relaxant and antispastic long thought to effectively diminish the verbal and muscular tics associated with TSdoes not in fact do so significantly in children. What it does apparently do is somehow make patients feel less "impaired" by the tics. And that, Singer concluded, did improve their overall condition, because TS patients often suffer from other problems such as attention-deficit hyperactivity disorder and obsessive-compulsive disorder.
The second study tested the effects of injecting botulinum toxin into muscles affected by tics in adult TS patients. The thought was that because the toxin paralyzes the nerve in the muscle, it would eliminate the tic. (Botulinum toxin has been used in this way cosmetically to treat wrinkles.) The participants, reports Anthony E. Lang of Toronto Western Hospital in Toronto, Ontario, Canada, experienced on average a 39 percent reduction in the number of tics per minute. Placebo recipients, in contrast, showed a 6 percent increase tics per minute. Unlike baclofen, however, botulinum toxin did not lead to overall improvement in TS symptoms.
"Learning which kinds of drugs suppress the tics the best may enable us to develop more effective treatments in the future," Singer remarks. "Testing medications in a rigorous setting represents the first step in identifying better therapies for TS."