Associations between the Five-Factor Model personality traits and psychotic experiences in patients with psychotic disorders, their siblings and controls.

Earlier studies indicated that personality characteristics contribute to symptomatic outcome in patients with psychotic disorders. The aim of the present study was to further explore this connection by examining the relationship between the Five-Factor Model (FFM) personality traits and a dimensional liability for psychosis. FFM traits according to the NEO-FFI and levels of subclinical psychotic symptoms according to the CAPE were assessed in 217 patients with psychotic disorders, 281 of their siblings and 176 healthy controls. Psychotic symptoms according to the PANSS were assessed in the patient group. Patients differed from siblings and controls on four of the five FFM traits, all but Openness. Siblings reported higher levels of Neuroticism than controls, but lower levels than patients. Particularly lower Agreeableness, and to a lesser degree, higher Neuroticism and lower Extraversion were associated with more severe symptoms in patients. Furthermore, higher Neuroticism and higher Openness were associated with higher levels of subclinical psychotic experiences in all three groups. Associations were strongest in patients. Our findings suggest that levels of Neuroticism increase with the level of familial risk for psychosis. Levels of Openness may reflect levels of impairment that distinguish clinical from subclinical symptomatology.