Initially described in the mid-1980s, cognitive disengagement syndrome (CDS; previously termed sluggish cognitive tempo) is a set of symptoms comprising excessive daydreaming, mental confusion, and hypoactivity that is distinct from attention-deficit/hyperactivity disorder and other psychopathology dimensions and independently associated with functional outcomes. This article provides a broad overview of the history of the CDS construct, its terminology, and the current state of the science. Although there has been a marked upsurge in research on CDS, including psychometrically rigorous assessment tools and an emerging pattern of findings across numerous domains of functioning, the existing literature base also points to the importance of marshaling an ambitious research agenda that can guide CDS into its next era. Ten key research domains and open questions are highlighted, including (1) developmental course of CDS across the lifespan, (2) mechanisms linking CDS to functional outcomes and impairment, (3) importance of gathering normative data, (4) clarifying CDS and unidimensional or multidimensional, (5) etiologies of CDS, (6) neurobiology and psychophysiology of CDS, (7) CDS as a transdiagnostic trait, (8) understanding individuals with elevated CDS, (9) promoting participatory approaches and valuing lived experience, and (10) the role of CDS for intervention. Implications of this research for possible conceptualizations of CDS as a distinct disorder, diagnostic specifier, or transdiagnostic dimension are discussed. The road ahead will require increased collaboration, creativity, and rigor to build theory, and, ultimately, support the well-being of individuals with this syndrome. (PsycInfo Database Record (c) 2025 APA, all rights reserved).