wikipedia: Sertraline

This is what wikipedia states about Sertraline:

Social phobia

Sertraline has been successfully used for the treatment of social phobia. In a flexible dosing study, it appeared that a higher dose range was needed for adequate response. Furthermore, improvement was achieved slowly, separating from the placebo response only by week six, and continuing to increase until week 12. The response was higher among the patients with later onset, especially adult onset, of the disorder.

Among the different rating scales, the clinician-rated global improvement demonstrated the highest difference vs. placebo, while the patient self-rated quality of life differed from placebo only modestly. The greatest improvement of quality of life was observed among the most impaired patients.[76] In addition to psychological components of social phobia, such as fear and avoidance, sertraline also ameliorated some physiological components, such as blushing and palpitations but not sweating and trembling.

In a four-way placebo-controlled comparison trial of sertraline and exposure therapy, sertraline performed significantly better than placebo, while the exposure therapy resulted in only marginal improvement. The combination of sertraline and exposure therapy was not significantly better than sertraline alone; however, it appeared that the response was achieved faster with the combined treatment.