Sarigül, AbdulselamiTuran, Mehmet EminAlkhulayfi, Abdulmohsen Mohammed AbdullahGómez Salgado, JuanYildirim, Murat2026-04-082026-04-082026Sarigül, A., Turan, M. E., Alkhulayfi, A. M. A., Gómez-Salgado, J., & Yıldırım, M. (2026). Development and initial validation of the toxic personality scale: exploring reliability, structure, and convergent validity. Psicologia: Reflexão e Crítica, 39(1). https://doi.org/10.1186/s41155-026-00383-41678-7153 (electrónico)https://hdl.handle.net/10272/28175Background: Toxic personality traits, which encompass behaviours and attitudes that negatively impact interpersonal relationships and personal well-being, have gained increasing attention in psychological research. However, a significant gap remains in developing reliable and culturally relevant measures to assess these traits. Objective: This study addressed a research gap by developing a new measure for determining toxic personality traits, the Toxic Personality Scale (TPS), and evaluating its reliability and validity across two samples of young Turkish adults. Methods: To develop the scale, two studies were conducted. Study 1 included 389 undergraduate students (78.66% male, 21.34% female) aged 18 to 48 years (M = 21.45, SD = 4.16). Study 2 involved 158 participants (72.78% female, 27.22% male) aged 18 to 35 years (M = 21.28, SD = 2.62). Participants completed the TPS and the Short Dark Triad through an online survey. Results: The exploratory and confirmatory factor analyses suggested that the TPS scale was unidimensional, with six items demonstrating a good internal consistency reliability estimate. The TPS also showed a significant positive relationship with the measure of narcissism. Conclusion: The findings suggest that the TPS is a valid and reliable tool for assessing toxic personality traits. These results support the TPS as a valuable instrument for use in both research and clinical settings to better understand and identify toxic personality traits in individuals.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Toxic personality scaleNarcissismValidityReliabilityTurkish young adultsjournal article10.1186/s41155-026-00383-4open access61 Psicología