Maladaptive Daydreaming in Adulthood: Theoretical Conceptualizations, Comorbidities, and the Role of Default Mode Network

This literature review examines how maladaptive daydreaming (MD) has been conceptualized in adult psychological and psychiatric research from 2002 to 2025. MD was initially described as excessive, immersive fantasy activity associated with distress and functional impairment (Somer, 2002), and subsequent work has debated whether it represents a distinct clinical syndrome or a maladaptive coping strategy that overlaps with established diagnostic categories. The review synthesizes major conceptual frameworks and classification debates, with a focus on “repeated clinical features and associated patterns reported in adult samples." In addition, it summarizes emerging neuroscientific accounts that link MD-related internally oriented cognition to large-scale brain systems involved in self-referential processing and mind-wandering, including the default mode network (DMN). Given the limited and heterogeneous neurobiological evidence, the review highlights key gaps in measurement, sampling, and causal inference and outlines directions for future research aimed at clarifying MD’s nosological status and mechanisms.