To evaluate the external validity of comorbid patterns of anxiety disorders among youth who presented to an anxiety disorders clinic, comorbid cases were compared to 'pure' anxiety disorder cases. Children and adolescents (N = 329; mean age = 10.04 years) and parents were administered structured interviews and four groups were formed, Pure Anxiety, Anxiety + Anxiety, Anxiety + Externalizing, and Anxiety + Depressive, and compared along with four external validation criteria: sociodemographics, clinical phenomenology, psychosocial, and family factors. All comorbid groups were more severe than the pure anxiety group on clinical phenomenology and psychosocial factors. The Anxiety + Depressive Disorders group was most severe on all criteria except sociodemographics. Results provide evidence for the external validity of comorbid diagnostic presentations among anxiety disorders, as there was differential meaningfulness in the diagnostic presentation of a pure anxiety disorder versus anxiety disorder comorbid with other disorders. Assessment and future research implications are discussed. (c) 2006 Elsevier Ltd. All rights reserved
