Sleep and Maladaptive Personality Traits: A Twin Study.

Sleep is essential for human functioning, but little attention has been paid to the interplay between sleep and maladaptive personality traits. We examined genetic and environmental associations between sleep and four maladaptive domains (MDs)-Negative Affectivity, Detachment, Disinhibition, and Psychoticism-within the framework of the DSM-5 Alternative Model of Personality Disorders (AMPD). We estimated phenotypic, genetic, and environmental variance and covariance using a twin study approach. Phenotypically, the four MDs showed small associations with sleep duration, medium associations with sleep efficiency, and large associations with sleep quality. A similar pattern was observed in genetic correlations, with Negative Affectivity and Detachment consistently showing the strongest associations. Multilevel Regression results based on the co-twin control design indicated that genetic factors only partially account for these relations. Whilst previous research has extensively focused on adaptive personality traits predicting sleep, our study highlights the importance of maladaptive traits as meaningful predictors of sleep health.