Linking repetitive negative thinking and insomnia symptoms: A longitudinal trait-state model.

Sleep disturbance is highly debilitating, and an abundance of research suggests that repetitive negative thinking (i.e., rumination, worry) may contribute to the development and maintenance of maladaptive sleep patterns, such as insomnia symptoms. Although repetitive negative thinking is often conceptualized as a 'trait' risk factor for anxiety-related disorders, it is unclear if it consists of time-varying (TV) or state-like features versus time-invariant (TI) or trait-like characteristics. Furthermore, it is unclear if it is the TV or TI components of repetitive negative thinking that contribute to insomnia symptoms that is commonly observed in anxiety-related disorders. In a 6-wave, 5-month longitudinal study, community participants (N = 1219) completed measures of rumination, worry, transdiagnostic repetitive negative thinking, and insomnia symptoms. A latent variable (trait-state-occasion) model was applied to the measures of repetitive negative thinking. The results showed that although estimates of TI factor variance and TV factor variance were both significant for latent repetitive negative thinking, worry, and rumination, the proportion of TI factor variance (0.82-0.89) was greater than the amount of TV factor variance (0.11-0.19). Although TV factor stability was statistically significant for latent repetitive negative thinking, rumination, and worry, the magnitude of the coefficients was small. Furthermore, regression weights for the latent repetitive negative thinking, rumination, and worry TI factor were significant and larger than those for the TV factor in predicting insomnia symptoms at each of the six time points. These findings suggest that repetitive negative thinking is largely TI, and it is this TI component that contributes to insomnia symptoms. Implications for conceptualizations of repetitive negative thinking as a predisposing and perpetuating factor in insomnia for anxiety and related disorders are discussed.