Validity and Measurement Invariance of Abbreviated Scales of the State-Trait Anxiety Inventory (STAI-Y) in a Population of Italian Young Adults

Giuseppe Valente Pierluigi Diotaiuti ^* Stefano Corrado Beatrice Tosti Stefania Mancone

• University of Cassino, Cassino, Italy

In this study, we evaluate the validity and measurement invariance of the 8-item scales of the State-Trait Anxiety Inventory (STAI) across gender and age. Originally developed by Spielberger (STAI-Y), these scales have been shortened to create more efficient versions without sacrificing psychometric robustness. A sample of Italian young adults, aged between 18 and 36 years, completed the abbreviated scales, demonstrating excellent internal consistency and convergent validity with the Endler Multidimensional Anxiety Scales (EMAS). Our results reveal that both the STAI-S-8 and STAI-T-8 maintain balanced factorial structures and robust anxiety measurement capabilities, as evidenced by significant correlations with the EMAS scales. Measurement invariance across gender and age was confirmed, indicating that these scales can reliably assess anxiety in young adults regardless of gender. However, limitations of this study include the absence of a clinical sample and the use of self-report measures, which may introduce subjective biases. The practical implications of these abbreviated scales are substantial for rapid anxiety assessment in clinical and research settings, allowing for timely interventions and a deeper understanding of psychological conditions. Future research should include clinical samples and diverse populations to further explore the effectiveness and applicability of the 8-item STAI scales, with particular attention to cultural differences in anxiety manifestation. In summary, the 8item STAI scales represent valid and reliable tools for measuring anxiety, offering practical benefits in terms of efficiency and accuracy.