BackgroundEarly exposure to trauma is a known risk factor for personality disorder (PD), but evidence for late-onset personality pathology following trauma in adults is much less clear. We set out to investigate whether exposure to war trauma can lead to lasting personality pathology in adults and to compare the mental health and social functioning of people with late–onset personality problems with those with PD.MethodsWe recruited patients who scored positively on the International Personality Disorder Examination (IPDE) in southern Croatia 15 years after the Croatian war of independence and used a semi-structured interview to establish when the person’s personality-related problems arose. All participants also completed Harvard Trauma Questionnaire, and measures of mental health and social functioning.ResultsAmong 182 participants with probable personality disorder, 65 (35.7%) reported that these problems started after exposure to war-trauma as adults. The most prevalent personality problems among those with late-onset pathology were borderline, avoidant, schizotypal, schizoid and paranoid. Participants with late-onset personality pathology were more likely to have schizotypal (75.4% vs. 47.3%) and schizoid traits (73.8% vs. 41.1%) compared to those with PD. Participants with late-onset personality pathology were three times more likely to have complex personality pathology across all three DSM-IV clusters compared to those with PD (OR = 2.96, 95% CI 1.54 to 5.67) after adjusted for gender and marital status. The prevalence of depression and social dysfunction were as high among those with late-onset personality pathology as among those with personality disorder.ConclusionRetrospective accounts of people with significant personality pathology indicate that some develop these problems following exposure to severe trauma in adulthood. Personality-related problems which start in adulthood may be as severe as those that have an earlier onset. These findings highlight the long term impact of war trauma on the mental health and have implications for the way that personality pathology is classified and treated.