Visual backward masking deficits in schizotypy

In visual backward masking, a target is followed by a mask impeding target perception. Visual backward masking is a potential endophenotype for schizophrenia because patients with schizophrenia and also their unaffected relatives show significant performance deficits compared to controls. If backward masking is an endophenotype, unaffected students with elevated schizotypal traits should also show relative backward masking impairments. In the past, research on endophenotypes has mostly focused on higher cognitive functions. For this reason, we also assessed performance in the widely used Wisconsin Card Sorting Test (WCST). We tested 40 healthy undergraduate students in the visual backward masking task and the WCST used in clinical studies before. All participants filled in a self-report schizotypy measure, i.e. the O-life questionnaire assessing schizotypy along three dimensions, i.e. unusual experience, cognitive disorganization, and introvertive anhedonia. We observed that both visual backward masking and the total number of errors in the WCST were impaired for students with high scores on the cognitive disorganization dimension. No significant differences were found for introvertive anhedonia scores or unusual experience scores. The present findings indicate that both tasks are potential endophenotypes along the schizophrenia spectrum. However, previous studies indicate that the backward masking task is more reliable than higher cognitive tasks (e.g. WCST). Because our findings were specific to cognitive disorganization, we suggest that this dimension is the most illness-relevant schizotypy dimension. Our results show further evidence that visual backward masking is a potential endophenotype for schizophrenia.