Validity and factor structure of the Czech GAD-7 across twenty samples and four independent translations

The Generalized Anxiety Disorder 7-item questionnaire (GAD-7) is a widely used screening tool for anxiety symptoms; however, its psychometric properties have not yet been comprehensively evaluated in the Czech population, where at least four independent and competing translations are commonly used. This study examined the factor structure, measurement invariance, reliability, and sensitivity to change of the Czech GAD-7 across 20 adult samples (N = 5529), including both general population and psychiatric patients. Two samples contained repeated measurements over two or four time points. Confirmatory factor analyses supported a unidimensional structure, consistent with the scale's original conceptualization and widespread use. Measurement invariance up to the residual level was established across gender, clinical status, and time, and-except for one translation containing a wording issue-also across translations, indicating that item functioning is highly robust to differences in wording. The GAD-7 demonstrated good internal consistency (median α =.86), moderate test-retest stability across major life events (r = .46-.53), and clear sensitivity to change during psychotherapy (ΔSE = 2.65; reliable change threshold ±5.2 points). Percentile-based Czech norms were developed for both general and psychiatric populations based on convenient samples. Overall, these findings provide strong empirical support for the GAD-7 as a reliable and valid measure of anxiety symptoms in Czech clinical and research contexts, enabling meaningful comparisons across populations and existing translations. The demonstrated robustness across translations and minimal sensitivity to specific wording informs future cross-linguistic adaptations and validation efforts.