Cross-sectional investigations, using the five-factor model of personality have evinced relationships among neuroticism, agreeableness, and psychotic symptoms. The current study examined these relationships via a prospective follow-up study with remitted first-episode psychosis patients. Baseline five-factor model personality profiles, diagnoses, symptom ratings, and premorbid adjustment ratings were followed by nine monthly ratings on Brief Psychiatric Rating Scale psychosis items in 60 first-episode patients. Valid baseline personality profiles were completed by 40 patients. Patients who had a return of symptoms scored higher on baseline neuroticism and agreeableness than those who remained in remission. Premorbid adjustment also predicted return of symptoms. After premorbid adjustment was controlled for, the agreeableness differences remained significant, but the neuroticism scores were no longer significantly different. It is concluded that lower agreeableness acts as a mediating variable in relapse. Further studies should clarify whether agreeableness is associated with specific biases in processing interpersonal information, and interpersonal behaviors.