Development and psychometric validation of the health anxiety scale in adults

Health anxiety influences how individuals interpret health-related uncertainty, seek health information, and engage with healthcare services. In digital health environments, these processes are increasingly shaped by online information, making e-health literacy an important factor in understanding health anxiety. Although adapted instruments are available in Turkish, studies developing concise scales for assessing health anxiety in general adult populations remain limited. This study aimed to develop and psychometrically validate a Health Anxiety Scale (HAS-9). As a secondary objective, the association between health anxiety and e-health literacy was also explored. This methodological and cross-sectional study included 479 adults aged 18–65 years. An item pool was generated through literature review, expert evaluation, and pilot testing. The dataset was randomly divided into two subsamples for exploratory and confirmatory factor analyses. Psychometric evaluation included content validity, internal consistency, test–retest reliability, convergent and discriminant validity, item response theory (IRT) analyses, differential item functioning (DIF), and measurement invariance testing. Criterion-related validity was examined through associations with e-health literacy. The analyses were generally consistent with a unidimensional nine-item scale. Confirmatory factor analysis provided only preliminary support for the proposed unidimensional structure, although model-fit limitations remained, particularly with respect to RMSEA. The scale showed high internal consistency (Cronbach’s α = 0.903), satisfactory convergent validity (composite reliability [CR] = 0.91; average variance extracted [AVE] = 0.61), and good temporal stability (intraclass correlation coefficient [ICC] = 0.835). As an exploratory criterion-related analysis, health anxiety showed a weak negative association with e-health literacy (r = −0.142, 95% CI [−0.228, −0.053], p = 0.002). The findings provide preliminary psychometric evidence for the HAS-9 in a general adult sample. However, the proposed measurement model should be regarded as provisional and requires further refinement and independent replication before broader research or applied use can be recommended. Within these limitations, the HAS-9 may provide a useful brief option for future research on health anxiety and related psychological and behavioral processes.