Poster Session: Visual System Assessment for Predicting a Transition to Psychosis.

Abstract

Visual system assessments are seldom regarded as a viable way to predict a future psychotic disorder. Here, we argue that may be a missed opportunity. From a large literature, we identify a set of visual tests that have distinguished individuals prior to or near the first psychotic episode or that have shown group differences independently of illness duration. Such tests have revealed moderate-to-large patient differences unexplainable by medication or generalized deficits. For example, self-reported visual perceptual distortions have already longitudinally predicted impending psychosis in large samples. Possibly predictive psychophysical tests include contrast sensitivity, backward masking, collinear facilitation, stereoscopic depth perception, contour integration, visual shape completion, and restricted fixational patterns during free viewing. Possible brain based markers include visual thalamo-cortical hyperconnectivity, decreased gamma band power during visual detection, and reduced occipital P1 amplitudes (EEG) during passive viewing. Promising retinal markers include reduced cone a- and b-wave amplitudes and photopic negative response (ERG). The foregoing assessments are often brief, well-tolerated, simple to administer, and well-described mechanistically. Across all major levels of analysis-from phenomenology to behavior to brain and retinal functioning-visual system assessment could help identify individuals who go on to develop a psychotic disorder.