Personality dimensions and neuropsychological performance in first-degree relatives of patients with schizophrenia and affective psychosis.

Several studies have found a significant increase in the prevalence of some personality disorders in the first-degree relatives of patients with schizophrenia; other studies have found subtle neuropsychological deficits in these relatives. However, little is known about the specificity of the personality traits reported or about the relationship between these traits and the neuropsychological deficits.One-hundred first-degree relatives of patients with schizophrenia (SR) and 88 first-degree relatives of affective psychotic patients (APR) completed the Eysenck Personality Questionnaire which measures extraversion, neuroticism, and psychoticism; they were also administered the National Adult Reading Test (NART), the Trail Making Test (TMT) and a Verbal Fluency Test (VFT). The male relatives of patients with schizophrenia scored significantly higher on the psychoticism scale than the male relatives of affective psychotic patients. In the SR group, there were significant correlations between the TMT performance and the extraversion scores and, between the IQ scores and the psychoticism scores. However, when logistical regression analyses were performed, none of the three personality scores predicted any of the neuropsychological performance in either the SR or the APR group. These results indicate some specificity as well as sex differences in the psychoticism dimension. Moreover, the relationship between the personality dimensions and the neuropsychological performance could indicate that psychoticism increases vulnerability to psychosis whereas extraversion decreases it.