This article proposes a unified systems neuroscience framework for schizophrenia, exploringthe hypothesis that REM–wake state boundary dysfunction may serve as a significant factorin the disorder’s pathophysiology. While traditional models emphasize primarydopaminergic or glutamatergic abnormalities, this framework suggests that theseneurochemical shifts may reflect downstream effects of REM-like neuralactivity infiltrating conscious wakefulness—a conceptual process termed “Inverse Lucidity.” By synthesizing findings from neurophysiology, predictive coding, and state-boundaryresearch, the model examines both positive symptoms (hallucinations, delusions) andnegative symptoms (social withdrawal) as potential manifestations of a disruption betweendreaming and waking perception. Building on foundational REM neuromodulation theories,this paper further develops and contextualizes the REM-intrusion hypothesis by integrating recent empirical data. The proposed framework aims to provide a novel perspective for identifying potential biomarkers and exploring state-based therapeutic interventions, in dialogue with established neurobiological models.