Performance-only Social Anxiety as a Distinct Clinical Profile: Evidence from Obsessive Beliefs, Alexithymia, and Cognitive Flexibility in Adolescent Girls with Social Anxiety Disorder.

Social anxiety disorder (SAD) in adolescent girls is clinically heterogeneous, yet the cognitive and emotional processes distinguishing performance-based, interaction-based, and combined presentations remain poorly characterized. In this case-control study, 219 adolescent girls aged 12-18 years were recruited from four child and adolescent psychiatry outpatient clinics and assigned, via K-SADS-PL-guided diagnostic evaluation, to four groups: performance anxiety only (SA - PA+; n = 52), social interaction anxiety only (SA + PA-; n = 50), combined social interaction and performance anxiety (SA + PA+; n = 67), and healthy controls (n = 50). Groups were compared on clinician-rated severity, social anxiety symptoms, obsessive beliefs (OBQ-44), alexithymic traits (TAS-20), and cognitive flexibility (CFI). A gradient boosting classifier, complemented by a sensitivity analysis excluding direct severity indicators, examined whether the three clinical phenotypes remained distinguishable beyond overall symptom load. Clinician-rated global severity (CGI-S) did not differ across the clinical groups, whereas the three presentations diverged across multiple cognitive-emotional domains, with large omnibus effects (ε² = 0.16-0.25). The SA - PA+ group showed lower obsessive beliefs and relatively preserved cognitive flexibility; the SA + PA- group was distinguished by reduced flexibility in generating alternative interpretations; the SA + PA+ group showed elevated alexithymic traits, longer illness duration, and the highest rate of previous psychiatric referral. Gradient boosting classified the three clinical groups with high cross-validated accuracy (0.96; macro-F1 = 0.96), decreasing only modestly when severity indicators were excluded (0.93). Performance-only, interaction-only, and combined SAD presentations reflect partially distinct cognitive-emotional profiles rather than a single severity gradient, which may inform assessment, case formulation, and treatment planning.