Selective serotonin reuptake inhibitors (SSRIs) are considered first-line treatments for generalized social phobia (GSP); however, many patients continue to have significant symptoms despite an adequate trial of an SRI. Topiramate, a drug, which targets the glutamate system in the brain, has been shown to improve symptoms of social phobia when used on its own and has also been used as an additive treatment in other anxiety disorders. This study will test the efficacy of adding topiramate to a subject's current SSRI in cases of GSP which are considered to be treatment-resistant. At the end of the study, participants will enter follow-up care with the study doctor.

McMaster University Medical Centre
Principal Investigator
Michael Van Ameringen, MD
Eligibility Criteria
  • Male or female outpatients 18 years or older with a primary diagnosis of obsessive compulsive disorder, who are currently being treated with an SRI (eg. paroxetine, fluoxetine, fluvoxamine, clomipramine, sertraline, citalopram, escitalopram) or SNRI (venlafaxine, desvenlafaxine, duloxetine) and continue to have OCD symptoms.
  • Physical examination, electrocardiogram, and laboratory findings without clinically significant abnormalities.
  • Willingness and ability to comply with the requirements of the study protocol.
  • Those taking psychotrophic medications, other than an SRI/SNRI are excluded.
The MacAnxiety Research Centre, 905-921-7644 or e-mail
Hamilton, ON