Momentary assessment research in psychosis.

There is an expanding interest to study psychosis in the realm of daily life. The study of the person in the context of daily life may provide a powerful addition to more conventional and cross-sectional research strategies in the study of psychosis. This article first discusses the nature of experience sampling research in psychosis and demonstrates the feasibility and validity of studies using the experience sampling method (ESM) in this patient group. Second, the article presents a review of all ESM research in psychosis with a special focus on (a) the phenomenology, (b) the etiology, and (c) psychological models of psychosis. Variability over time and the dynamic interplay with the environment were found to be essential features of the positive symptoms of psychosis, whereas behavioral patterns as well as self-reported affect in daily life reality might be essential when studying negative symptomatology. ESM contributes to a better understanding of the interplay between psychotic experiences and environmental features, such as stress or cannabis exposure. Finally, the study of symptomatic variability may fuel new research into psychological models and treatment of psychosis and the study of the person-environment interplay may foster new Gene x Environment interaction studies.