Color Perception in Patients with Schizophreniza and Their Healthy First-degree Relatives: A Cross-sectional Study

Endophenotypic markers are an important area of study for a better understanding of the biological basis of disorders such as schizophrenia. Our study evaluated color vision as a potential endophenotypic marker in schizophrenia.

This was a cross-sectional study at a tertiary care center with 39 patients diagnosed with schizophrenia and 39 healthy first-degree relatives (FDRs). After screening for ocular disorders and color blindness, all participants underwent the Farnsworth-Munsell D-100 test for color perception, the Montreal Cognitive Assessment (MoCA), and a symptom severity assessment with the Positive and Negative Syndrome Scale. Statistical analyses included t tests, correlations, and regression models.

All patients demonstrated poor color discrimination (total error score [TES] > 100), compared with 66.7% of FDRs. The mean TES of patients was 225.5 ± 64.3, and that of FDRs was 143.7 ± 50.9, both indicating impaired color discrimination. This deficit was not specific to any one color axis. Patients had significantly lower MoCA scores (20.5 ± 5.1) compared to FDRs (25 ± 2.7) (p < .001). Color perception deficits correlated positively with negative symptom scores (ρ = 0.39, p = .04) and negatively with MoCA scores (ρ = -0.44, p = .005). Regression analysis indicated that cognitive function was the strongest predictor of color perception impairment. Among FDRs, TES correlated significantly with age and MoCA scores.

Patients with schizophrenia exhibited marked impairments in color discrimination, and this was shared with FDRs. This suggests that impaired color vision may represent a potential endophenotypic marker of schizophrenia, warranting further longitudinal research.