Development and validation of the main character syndrome scale (MCS-10): A psychometric investigation among young adults.

Main Character Syndrome (MCS), the tendency to experience and present one's life as a protagonist-centered narrative, has emerged as a culturally relevant construct but lacks empirical operationalization. Based on narrative identity, narcissism, and digital self-presentations, we constructed and tested the Main Character Syndrome Scale (MCS-10) on two independent samples of Lebanese young adults. Across two independent samples (Study 1 N = 135; Study 2 N = 263), results supported a coherent unidimensional structure (CFA: CFI = 0.976, TLI = 0.969, RMSEA = 0.045) with strong reliability (α = 0.861, ω = 0.862). The MCS-10 demonstrated significant correlations with identity diffusion (r = 0.677), social media addiction (r = 0.630), and narcissism (r = 0.564), all ps < 0.001, while remaining empirically distinct from these constructs (HTMT ratios <0.85). Identity diffusion emerged as the strongest correlate in the multivariate model of MCS, suggesting that protagonist-centered self-perception is consistent with an identity-scaffolding interpretation. The MCS-10 offers a brief, psychometrically valid instrument for assessing a culturally salient yet previously unmeasured pattern of self-perception, advancing research on identity processes in digitally mediated environments.