Attention and Executive Function Impairments in Unaffected Siblings of Patients with Schizophrenia

Abstract Objective: To compare executive function and attention of patients with schizophrenia, their siblings, and healthy controls. Patients and Methods: The Wisconsin Card Sorting Test and Continuous Performance Test were administered to 50 patients with schizophrenia, 50 unaffected siblings of patients with schizophrenia, and 45 healthy controls. Results: Patients and their siblings performed worse than the healthy controls in the Wisconsin Card Sorting Test (p Conclusion: The results support not only that patients with schizophrenia have attention and executive function impairments, but also their unaffected siblings have some cognitive function impairments. Key words: Attention, Cognitive function, Schizophrenia, Siblings Introduction The symptoms of schizophrenia can be divided into 4 dimensions: positive symptoms, negative symptoms, cognitive deficits, and affective symptoms. (1) Although cognitive deficits have not yet been included in the diagnostic criteria of schizophrenia, they are one of the important core manifestations of this disorder and provide important diagnostic information, both in the phenotypic and prodromal phases. In addition, they may also lead to new clues to the treatment of this disorder. Genetics is an important aspect in the study of schizophrenia. With the use of neuropsychological testing instruments, the phenotype of the cognitive deficits of patients with this disorder, which is regarded as independent of positive and negative symptoms, may be investigated. (2,3) The results of previous studies indicate that the siblings of patients with schizophrenia possess similar cognitive deficits to those manifested in patients with schizophrenia. (4-6) However, there has been little research in this area in Chinese people. In this study, attention and executive function of patients with schizophrenia, their siblings, and healthy controls were investigated. It is hypothesised that both the patients with schizophrenia and their siblings manifest cognitive deficits compared to normal controls. Patients and Methods Participants There were 3 groups of participants, as shown below. All participants were interviewed by 2 psychiatrist investigators who made the diagnoses. Group 1 comprised 50 patients with schizophrenia recruited from the inpatient and outpatient units of the Department of Psychiatry of the Second Xingya Hospital of Central South University in Changsha, China. The inclusion criteria were as follows: * patients met the diagnostic criteria of schizophrenia or schizophreniform disorder described in DSM-IV * age within 18 to 50 years * no history of receiving electroconvulsive therapy * no chronic neurological disorders or severe medical disorders * no history of alcohol- or substance-abuse * no colour blindness. All patients were taking antipsychotic medication, with 22 taking clozapine and 28 taking risperidone. The illness duration of the patients varied from 1 to 375 months (median, 5 months). Group 2 comprised 50 siblings of patients with schizophrenia, with 1 sibling from each family of 1 patient with schizophrenia. The inclusion criteria were the same as for group 1 except that they were not required to meet the diagnostic criteria of any psychiatric disorders. Each participant and his/her corresponding sibling with schizophrenia had the same biological parents. Group 3 comprised 45 healthy controls, who were physicians, nurses, or employees from the Second Xingya Hospital. …