It has been suggested that social phobia may be characterized by two interpretation biases. First, a tendency to interpret ambiguous social events in a negative fashion. Second, a tendency to interpret unambiguous but mildly negative social events in a catastrophic fashion. To assess this possibility, patients with generalized social phobia, equally anxious patients with another anxiety disorder, ... [Show full abstract] and non-patient controls were presented with ambiguous scenarios depicting social and non-social events, and with unambiguous scenarios depicting mildly negative social events. Interpretations were assessed by participants' answers to open-ended questions and by their rankings and belief ratings for experimenter-provided, alternative explanations. Compared to both control groups, patients with generalized social phobia were more likely to interpret ambiguous social events in a negative fashion and to catastrophize in response to unambiguous, mildly negative social events.