Adaptation and Validation of the Polish Version of the Narrative Identity Self-Evaluation Scale (NISE-PL)

This study aimed to adapt and validate the Polish version of the Narrative Identity Self-Evaluation Scale (NISE), a self-report instrument designed to assess narrative identity across adaptive and maladaptive dimensions. A community sample of adults (N = 336) completed the NISE along with established measures of narrative identity (ANIQ, IAN), self-concept clarity (SCCS), depression (PHQ-9), anxiety (GAD-7), maladaptive personality traits (PiCD), and level of personality functioning (SIFS). Confirmatory factor analysis supported the four-factor structure of the scale, with some translation-specific cross-loadings identified. Internal consistency was adequate across all subscales (α = .76–.81). Criterion validity analyses showed that Autobiographical reasoning, Narrative structure, and Positive themes correlated positively with other narrative measures. In contrast, Narrative identity disturbances correlated negatively with self-concept clarity and positively with psychopathology. Importantly, hierarchical regression indicated that NISE dimensions provided incremental validity beyond maladaptive traits in predicting impairments in personality functioning. Together, these findings support the Polish NISE as a reliable and valid tool for capturing adaptive and maladaptive aspects of narrative identity in community populations, with promising potential for future use in clinical settings.