Stage-dependent sensitivity to Muller-Lyer visual illusion in schizophrenia patients

Rationale: Schizophrenic patients show perceptual deficits, which may be detected in visual illusion tasks. Previous studies found that chronic patients show increased sensitivity to Muller-Lyer illusion as the disorder progresses, although there are a few conflicting reports in the scientific literature. To address these issues, moderate and chronic schizophrenic patients were tested on the Brentano version of the Muller-Lyer illusion task. Their performance was compared to first-degree relatives and unrelated matched controls. Chronic patients showed increased susceptibility to the illusion. Performance on the visual illusion task was not correlated to the number of years since disease onset, medication or (Positive and Negative Syndrome Scale) PANSS scores. The lack of association between illusion sensitivity and PANSS score may reflect the absence of the perceptual dimension in this scale. Based on these results, we suggest that susceptibility to the Muller-Lyer illusion is associated with the stage of schizophrenia rather than disease length.

Automated summary

Moderate and chronic schizophrenic patients showed increased susceptibility to the Muller-Lyer illusion, which was not correlated with disease duration, medication or PANSS scores. This suggests that illusion susceptibility is associated with the stage of schizophrenia rather than disease length.