Adaptation and Validation of the Parental Stressor Scale: NICU for Spanish Populations

Background/Objectives: Parental stress during neonatal intensive care unit (NICU) admission affects parental well-being, bonding, and neonatal outcomes. Reliable assessment requires instruments adapted to the linguistic and cultural context of each population. This study aimed to adapt the Parental Stressor Scale: NICU (PSS:NICU) for use in Spain and evaluate its psychometric properties. Methods: The adaptation comprised forward translation, back-translation, expert review, pilot testing with cognitive debriefing (n = 15), and psychometric evaluation. The adapted scale was administered to 160 parents (80 mothers, 80 fathers) of NICU-admitted neonates; 159 cases were retained for analysis. Internal consistency was assessed with Cronbach's alpha. Exploratory factor analysis (EFA; maximum likelihood, Promax rotation) with parallel analysis examined the factor structure. Confirmatory factor analysis (CFA) tested the original four-factor model, and a second-order model with five first-order factors was subsequently evaluated. Results: Internal consistency was excellent (total α = 0.968; subscales α = 0.866-0.961). Parallel analysis supported a five-factor EFA solution over a four-factor solution. CFA of the original four-factor model yielded poor fit (CFI = 0.755, TLI = 0.737, RMSEA = 0.125). A second-order model with five first-order factors and one general stress factor improved fit (CFI = 0.819, RMSEA = 0.107), though indices remained below conventional thresholds. Standardised factor loadings were moderate to high (0.57-0.96). Conclusions: The Spanish PSS:NICU demonstrates excellent reliability and provides preliminary evidence supporting its use for research and clinical assessment. The original four-factor structure was not replicated; the data suggest a five-factor organisation with evidence of a higher-order stress construct. Structural validity requires confirmation in larger, independent samples.