Contrast sensitivity and subjective visual disturbances across the psychosis continuum

Subjective visual disturbances and objective visual deficits are common across the psychosis spectrum. Few investigations have tested them in the same sample to ask whether subjective disturbances may arise from low-level visual processing deficits. This study assessed whether reduced contrast sensitivity (CS), a low-level visual processing deficit in people with schizophrenia (PSZ), may contribute to subjective visual disturbances across the psychosis spectrum.

PSZ (n = 54) and controls (n = 54) matched for gender, age, and race/ethnicity, together with High PLE (n = 55) and Low PLE (n = 45) matched for gender, age, race/ethnicity, education, and IQ completed a CS task and the Bonn Scale, a structured interview assessing visual distortions. Group differences in CS and Bonn scores as well as their correlations with social risk factors were evaluated. In addition, the Bonn Scale's factor structure was examined.

PSZ and High PLE endorsed more distortions than controls. In PSZ, distortion severity, but not CS, correlated with social risk factors and clinical symptoms. Only PSZ showed reduced CS, and no associations between distortions and CS were observed.

Findings do not support a bottom-up account of visual distortions; instead, they may arise from higher-order processes.