Cognitive Disengagement Syndrome (CDS) is a clinical construct characterized by symptoms such as excessive daydreaming, mental confusion, slowed behavior, and reduced cognitive and motor activity. Increasing evidence suggests a potential overlap between CDS and Emotional Dysregulation (ED), a transdiagnostic construct associated with difficulties in regulating emotional responses. This narrative review synthesizes current empirical findings and theoretical perspectives on the co-occurrence of CDS and ED, with a particular focus on insights provided by behavioral genetics—especially twin studies. We describe the core principles and models used in twin research and evaluate how they have been applied to disentangle genetic and environmental contributions to these phenotypes and their overlap. While some studies support a shared etiology between CDS and ED, particularly through non-shared environmental influences, research in this area remains limited and conceptually fragmented. The review identifies critical knowledge gaps, including the lack of longitudinal studies, inconsistent definitions of ED, and limited exploration of developmental trajectories. We argue that future twin studies are essential for clarifying these unresolved issues. Nonetheless, limitations include the scarcity of twin-based studies directly examining the CDS–ED association and methodological inconsistencies across the existing literature.
