Abstract
Personality disorders have been traditionally framed as enduring dispositional conditions. Yet accumulating evidence suggests that they also reflect dynamic patterns of contextual adaptation. In this paper, we develop a formal framework that partitions personality stability into two components: an enduring portion (which is retained perfectly over time) and an adaptable portion (which dissipates over time, at either a fast or slow rate). After validating the model in computer simulations, we conduct a meta-analysis of 12 longitudinal investigations (N=17,785), yielding 145 test-retest correlations that quantify the stability of all personality conditions over 18 years. We then apply our formal model on these meta-analytic stability estimates to quantify the extent to which personality disorders are enduring vs. adaptable over time. Results indicate that most of personality pathology (60-70%) is adaptable over 18 years’ time, though it dissipates at a moderate rate (R≈55%). We conclude by suggesting that there is no formal distinction between personality pathology and psychopathology and outline a program aimed at studying all mental disorders as personality disorders.