Emerging adults as an age group are significantly struggling with their mental health (Kirtley et al., 2019). A thorough comprehension of both the adaptive and maladaptive side of their psychological adjustment should be based on the developmental task these youngsters face, namely identity development (Erikson, 1950). However, theoretical and methodological shortcomings in the available literature prevent an in-depth understanding of the exact nature of the identity-adjustment relationship, undermining their theoretical and clinical value. From a theoretical point of view, this research project proposes an integration between contemporary identity theory (Luyckx et al., 2006; 2008) and schema theory (Young et al., 1999; 2003), which will lead to to a more fine graded understanding of the relationship between identity and psychological adjustment. From a methodological point of view, these relationships will be investigated using innovative methodological designs and appropriate analytical strategies. In a first work package, several research objectives will be answered in a large-scale longitudinal study in the general community spanning 4 time points. In a second work package, a study in a clinical sample will be set-up, strengthening the practical implications of this research project.