Identifying psychiatric disorders rather than psychiatric symptoms might help to distinguish patients with psychogenic nonepileptic seizures (PNES) from those with epileptic seizures (ES). Patients with PNES (n=35), patients with ES (n=35), and healthy controls (n=37) were compared with respect to the prevalence of psychiatric disorders in this study. We tested the predictive power of having axis I psychiatric disorders, as well as personality disorders, in distinguishing ES from PNES. There was no significant difference between the patient groups in the prevalence of axis I psychiatric disorders. Personality disorders were more prevalent in the PNES group than in the ES group (P<0.05). Having a personality disorder was the only predictor for the PNES group. Having a personality disorder seems to be a more significant predictor for PNES than having an axis I psychiatric disorder. Greater attention should be paid to personality disorders in the differentiation of PNES and ES and the provision of effective treatment.