Background. While psychiatric epidemiology often focuses on the causal relationship between environmental adversity and the individual (e.g. environment to person), individuals probably make important contributions to the quality of their environments (person to environment).

Method. In a population based sample of >7000 male and female adult twins, we examined the relationship between the personality trait of neuroticism (N) and the occurrence of stressful life events (SLEs) and the quality of interpersonal relationships (IPR). We compared the magnitude of the prediction of twin 1's self-reported SLEs and IPR from: (i) twin 1's self-reported N; (ii) twin 2's report of twin 1's N; and (iii) twin 2's report of twin 2's N in monozygotic pairs.

Results. In our entire sample, self-report N significantly predicted the occurrence of most SLEs and all dimensions of IPR. Using the co-twin's report of N produced associations that were of the same magnitude for SLEs and modestly weaker for IPR. In monozygotic pairs, the level of N in one twin predicted SLEs and IPR in the co-twin at levels similar to those found for the co-twin's report of N. Repeating these analyses with a prospective subsample produced similar results.

Conclusion. An individual's personality in adulthood plays a significant role in influencing exposure to some forms of environmental adversity and this association is not the result of reporting bias. Furthermore, this relationship is largely mediated by a common set of familial factors that predispose both to a ‘difficult’ temperament and to environmental adversity. Developmental models of psychiatric illness should adopt an interactionist view of individuals and their environment (person and environment).