An empirical approach to subtype identification in individuals with socialphobia

Background. The present study used cluster analysis procedures to identify empirically subgroups of patients with social phobia in a large clinical sa mple. Method. The Liebowitz Social Anxiety Scale (LSAS) was administered to 382 p atients from several studies of the treatment of social phobia. LSAS fear r atings were summed into four subscale scores (social interaction, public sp eaking, observation by others, eating and drinking in public) based on a pr evious factor analytical study of the LSAS, In order to produce a stable an d robust solution, these factor scores were submitted to a two-stage cluste ring procedure consisting of an agglomerative-hierarchical clustering metho d followed by an iterative non-hierarchical clustering method. Results. Three patient subgroups were identified based on their pattern of feared social situations on the LSAS. These groups were labelled: (1) perva sive social anxiety; (2) moderate social interaction anxiety; and (3) domin ant public speaking anxiety. Clusters differed significantly on age and age of social phobia onset, as well as on measures of social anxiety, general anxiety and depressive symptomatology. Clusters also differed in the percen tage of assigned patients who met criteria for the generalized subtype of s ocial phobia and avoidant personality disorder. Conclusions. The results provide empirical support for the existence of thr ee subgroups in a clinical sample of individuals with social phobia and con tribute to the growing evidence for the heterogeneity of social phobia. Fur ther study of the conceptual, clinical and aetiological significance of the se subgroups is needed.