Although the study included only 13 patients, the preliminary results are promising for persons who have found no relief using other medications and cognitive behavioral therapy, said the first author, Vladimir Coric, M.D., assistant clinical professor in the Department of Psychiatry and director of the Yale OCD clinic.
"Riluzole appears to have significant antiobsessional, antidepressant, and antianxiety properties," said Coric, who will be presenting the data Friday at the Obsessive-Compulsive Foundation annual conference in San Diego.
OCD currently is treated with serotonin reuptake inhibitors, cognitive behavioral therapy and dopamine antagonists, which reduce symptoms in 40-60 percent of patients. "However, a number of patients remain dramatically symptomatic even with the combination of pharmacotherapy and cognitive behavioral therapy," Coric said.
OCD symptoms include obsessive checking, cleaning, washing, counting, hoarding, touching, tapping, ordering, arranging, rubbing, and other repetitive behaviors. Coric said treatment-resistant OCD is one of the few psychiatric indications for neurosurgical intervention. "Novel therapeutic strategies are urgently needed," he said.
Since recent neuroimaging studies suggest that individuals with OCD have abnormalities in corticostriatal glutamate function, Coric and his colleagues tested riluzole, a glutamate modulating agent, on patients with OCD. Glutamate is the most abundant excitatory neurotransmitter in the brain, but when in excess may cause neurotoxicity. Seven of the patients treated with riluzole experienced a 35 percent reduction in symptoms and five were categorized as responsive to the treatment. One patient left the study.
"The use of glutamate modulating agents, such as riluzole, may represent a novel treatment intervention for certain anxiety and mood disorders," Coric said.
Co-authors include Sarper Taskiran, M.D., Christopher Pittenger, Suzanne Wasylink, Daniel Mathalon, M.D., Gerald Valentine, John Saksa, Yu-te Wu, Ralitza Gueorguieva, Gerard Sanacora, M.D., and Robert Malison, M.D. John Krystal, M.D., was senior author.
The study was supported in part by the NARSAD Young Investigator Award, the National Institute of Alcohol Abuse and Alcoholism, and the National Institute of Health.
Biological Psychiatry (Online July 5, 2005)