Abstract
Research on Instagram addiction (IA) has examined a range of psychological and socio-relational factors to explain the addiction, including personality traits, self-esteem, mental health, social approval, and fear of missing out (FoMO), among others. However, no study has integrated both social influence processes (subjective norms, group norms, and social identity) and meaningful relationships (attachment, dyadic, and friendship ties) with FoMO in relation to IA. This study examined the interplay among social influence processes, meaningful relationships, and FoMO on IA, as well as the moderating roles of subjective and group norms on the indirect effect of anxious attachment on IA via FoMO. The sample consisted of 180 Italian young adults (aged 18-30) who completed validated questionnaires on IA, social influence, relationships, and FoMO after providing consent. Social media use was also explored through an open-ended question. Results indicate that FoMO, social and group norms, and group identification significantly contribute to IA. Anxious attachment had a significant indirect effect on IA via FoMO, with subjective and group norms moderating this association. Qualitative analysis of open-ended responses enriched the understanding of young adults' social media use. These findings highlight the importance of social influence, relationships, and FoMO in young adults' Instagram engagement and suggest directions for addressing problematic use in this group.