Abstract. This study determined the impact of social support and existential gratitude on life satisfaction among young adults affected by parental substance use and whether social support mediates the relationship between existential gratitude and life satisfaction. It utilized a quantitative research design, specifically mediation analysis, to address its objective. The study was conducted in Calamba City and used simple random sampling to gather individuals aged 18-25 affected by parental substance use. The study used three adopted survey questionnaires, namely the Multidimensional Scale of Perceived Social Support (MSPSS), Existential Gratitude Scale (EGS), and Satisfaction with Life Scale (SWLS). Regression analysis discovered that existential gratitude has a calculated r-square of 0.386 that predicts social support; a computed r-square of 0.340 indicates that social support predicts life satisfaction; a computed r-square of 0.334 indicates that existential gratitude predicts life satisfaction. Moreover, the bootstrap method and Sobel test were employed to determine whether social support mediated between existential gratitude and life satisfaction. After data analysis, it was found that social support only partially mediated the relationship between existential gratitude and life satisfaction by 39.2%. Existential gratitude still affected life satisfaction, with or without the presence of social support. This implies that existential gratitude directly impacts life satisfaction and can indirectly enhance it by fostering social support. With this, future programs aiming to enhance the life satisfaction of young adults affected by PSU may focus on enhancing existential gratitude and life satisfaction, as both were found to improve life satisfaction.

Keywords: Existential gratitude; Life satisfaction; Mediation; Parental substance use; Social support; Young adults.