A narrative review of clinical stages of psychosis addressing neurocognitive, sleep, and sleep spindle alterations.

Abstract

Prodromal phases in psychotic disorders, or pre-psychotic states, constitute a critical window during which cognitive and sleep-related changes emerge, offering important insights into the course of the disorder. Determining underlying mechanisms behind the progression of clinical stages of psychosis requires an understanding of the neurocognitive characteristics, sleep patterns, and sleep spindle features associated with these phases. Sleep spindles are suggested to be strong indicators for predicting general intelligence, memory and basic learning skills in both healthy individuals and clinical groups. Changes in sleep structure, decrease in spindle activity, and disruption of sleep-related learning seem to be important in explaining dysfunction in psychosis. For this reason, defining how these processes are affected during the prodromal period, prior to the first psychotic episode, may provide evidence for the underlying mechanisms of the disorder. In particular, sleep spindles may provide insight into neurophysiological functioning and the disorder's pathophysiology. This narrative review aims to summarize the clinical stages of psychosis, highlight the significance of neurocognitive impairments, and explore the role of sleep spindles in psychotic conditions, as well as their potential implications for future research. A comprehensive analysis of the literature between 1990 and 2025, from major databases including PubMed, Web of Science, PsycINFO, and Scopus, was conducted, with a focus on studies examining clinical stages of psychosis, neurocognitive impairments, changes in sleep, and sleep spindle activity in individuals exhibiting pre-psychotic symptoms.