<p>Problematic social media use (PSMU) has become a significant focus of research, particularly among young adults, due to its association with behavioral addiction and its potential effects on well-being. The Bergen Social Media Addiction Scale (BSMAS) is a widely recognized tool for assessing PSMU. This study sought to adapt the BSMAS to Spanish and evaluate its psychometric properties in a sample of Spanish young adults.</p><p>Results demonstrated that the Spanish BSMAS shows adequate reliability (Cronbach’s alpha = 0.85) and suggests a one-dimensional structure of problematic social media use (χ² (9) = 78.2, CFI = 0.91, TLI = 0.85, RMSEA = 0.07, NFI = 0.90). Measurement invariance testing suggests the scale may be applicable across genders, establishing configural, metric, and scalar invariance, with minimal residual differences noted. Concurrent validity was further explored through correlations with external measures: BSMAS scores showed a moderate positive correlation with the Fear of Missing Out (FOMO) scale (r = .50 to .70) and a significant negative correlation with the Life Satisfaction Scale (SWLS) (r = -.40 to -.60). Multiple regression analysis explained 61.7% of the variance in PSMU (adjusted R² = 0.606). Age (p = 0.01), FOMO State (p &lt; 0.001), FOMO Trait (p &lt; 0.001), and Satisfaction with Life (p = 0.01) emerged as significant predictors. Gender (p = 0.52) and relationship status, being in a relationship (p = 0.47) or single (p = 0.13), were not significant. Educational variables showed that being currently enrolled in studies (p = 0.001) and studying for a Doctorate (p = 0.04) significantly predicted PSMU, while being in Middle School (p = 0.77) or at University (p = 0.08) did not.</p><p>These findings indicate that the Spanish BSMAS may be a reliable instrument for measuring PSMU in Spanish young adults, providing a tool for future research and practical applications in this population.</p>