The Self- and Parent-Report Versions of the Spence Children’s Anxiety Scale: Internal Structure and Multi-Informant Construct Validity in Portuguese Adolescents and Their Parents

The Spence Children’s Anxiety Scale (SCAS) and its parent version (SCAS-P) are widely used and psychometrically supported measures that contribute meaningfully to multi-informant assessment of adolescent anxiety. However, their internal structure and convergent validity within a multitrait–multimethod framework have not been examined. This study addressed this gap by evaluating the internal structure of the SCAS and SCAS-P in Adolescent (n = 302; 12–19 years; 60.3% female) and Parent samples (n = 314; 30–70 years; 83.8% female). The original six-factor model showed acceptable fit and was retained for both the SCAS and the SCAS-P measuring separation anxiety, social anxiety, obsessive-compulsive symptoms, panic/agoraphobia, generalized anxiety, and fear of injury. A nested Dyad sample (n = 198) was then used to test the multitrait–multimethod construct validity of this model. Results generally supported multi-informant construct validity of the SCAS and the SCAS-P, though the specific perspective of each informant introduced substantial unique variance into the scores. Furthermore, the validity of specific dimensions was qualified: multi-informant convergence was limited for obsessive-compulsive symptoms, and generalized anxiety was insufficiently distinct from the remaining measures. Still, findings support the SCAS and SCAS-P as useful and flexible tools for assessing adolescent anxiety as reported by the adolescent and/or their parents, supporting the assessment of anxiety-related difficulties and providing a multi-informant understanding of adolescents’ anxiety symptoms in both research and clinical contexts.