• Social Phobic Disorders Severity and Change Form [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  
• Liebowitz Social Anxiety Scale (LSAS) [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  

• Social Phobia and Anxiety Inventory [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  
• Quality of Life Enjoyment and Satisfaction Questionnaire [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  
• Liebowitz Self-Rated Disability Scale [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  
• Range of Impaired Functioning Tool [ Time Frame: Measured at Months 3, 6, and 9 post-treatment ] [ Designated as safety issue: No ]
  

Social anxiety disorder (SAD) is among the most common psychiatric conditions and is associated with significant distress and dysfunction in social situations. Although treatment with cognitive-behavior therapy (CBT) is known to help remedy SAD, many patients do not respond to this treatment and most do not reach full recovery. In CBT, patients undergo repeated and prolonged exposure practices to feared social situations to learn better ways to deal with anxiety in these settings. Exposure therapy is based on animal models of extinction of conditioned fears, and recent animal research has identified some of the core pathways and neurotransmitters involved in fear extinction. D-cycloserine (DCS) is a drug that appears to facilitate learning and the process of extinction of conditioned fear in both animals and humans. This study will assess the effectiveness of DCS combined with CBT in treating people with SAD.

Participants in this double-blind study will be randomly assigned to an active or control group. All participants will attend 18 study visits at the Center for Anxiety and Related Disorders over a 12-month period. There will be 12 CBT sessions of 90 minutes each and 6 assessment visits. The CBT sessions will help participants to become more comfortable with social situations. During 5 of the CBT sessions, participants will receive a pill containing either DCS or sugar (placebo). Assessment visits will include interviews, self-report questionnaires, and laboratory tests. These visits will occur at Weeks 1, 7, and 12 during treatment and at Months 3, 6, and 9 post-treatment.