Neurocognitive Functioning in Schizophrenia, their Unaffected Siblings and Healthy Controls: A Comparison

Neurocognitive functions are considered to be reliable endophenotypes for schizophrenia. This study aimed to study the neurocognitive functioning of unaffected siblings of patients with schizophrenia and compare the same with a group of patients with schizophrenia and a group of healthy controls.

Three study groups, that is, unaffected siblings of patients with schizophrenia, patients of schizophrenia and healthy controls, each group comprising of 20 participants were evaluated on Wisconsin Card Sorting Test, Brief Visuospatial Memory Test-Revised, Hopkins Verbal Learning Test-Revised, Wechsler Adult Intelligence Scale and Digit Symbol Test.

Compared to healthy controls, unaffected siblings of patients with schizophrenia performed poorly on the tests of short-term verbal learning and memory, but no significant differences were seen between the two groups for executive functions, visual learning and psychomotor speed, concentration and graphomotor abilities. However, when compared with patients with schizophrenia, unaffected siblings performed poorly on the tests of executive functions, visual memory, verbal memory, psychomotor speed, concentration and graphomotor abilities.

Cognitive markers like verbal memory deficits can distinguish unaffected siblings of schizophrenia from healthy controls and serve as an endophenotype for schizophrenia.