Search

Study Objectives: Long and short sleep duration are associated with greater risk of developing post-traumatic stress disorder (PTSD); however, it is unknown how genetic and environmental influences affect this relationship. Thus, we investigated the association between sleep duration and PTSD symptoms using twin models., Methods: Data were obtained from 1865 monozygotic and 758 dizygotic twin pairs enrolled in the community-based Washington State Twin Registry. PTSD symptoms were assessed using the Impact of Events Scale (IES). A classical twin model decomposed the variances of sleep duration and IES score into additive genetic, shared environmental, and unique environmental components. We used correlated factor models to examine the moderation of variance components of sleep duration and IES., Results: Shorter and longer sleep duration were associated with higher IES scores with a quadratic association (p < 0.001). The heritability of sleep duration was 36%, and IES 31%. Variance in sleep duration attributable to shared (b1C1 = 2.91, 95% CI = 1.40 to 4.43; p < 0.001) and unique (b1E1 = 0.18, 95% CI = 0.10 to 0.27; p < 0.001) environment was moderated by IES score. Similarly, but to a lesser extent, variance in IES attributable to additive genetics (b1A2 = -0.23, 95% CI = -0.45 to 0.00; p = 0.048) was moderated by sleep duration., Conclusions: Greater PTSD symptom severity was associated with short and long sleep duration. Increasing PTSD symptoms increased variability in sleep duration primarily via shared environmental factors, whereas decreasing sleep duration increased variability in PTSD symptoms primarily via additive genetic factors. This suggests childhood experiences affect variability of sleep duration and genetic factors affect the variability of PTSD symptoms in trauma-exposed individuals., (© Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.)

Study Objectives: We used quantitative genetic models to assess whether area-level deprivation as indicated by the Singh Index predicts shorter sleep duration and modifies its underlying genetic and environmental contributions., Methods: Participants were 4,218 adult twin pairs (2,377 monozygotic and 1,841 dizygotic) from the University of Washington Twin Registry. Participants self-reported habitual sleep duration. The Singh Index was determined by linking geocoding addresses to 17 indicators at the census-tract level using data from Census of Washington State and Census Tract Cartographic Boundary Files from 2000 and 2010. Data were analyzed using univariate and bivariate genetic decomposition and quantitative genetic interaction models that assessed A (additive genetics), C (common environment), and E (unique environment) main effects of the Singh Index on sleep duration and allowed the magnitude of residual ACE variance components in sleep duration to vary with the Index., Results: The sample had a mean age of 38.2 y (standard deviation [SD] = 18), and was predominantly female (62%) and Caucasian (91%). Mean sleep duration was 7.38 h (SD = 1.20) and the mean Singh Index score was 0.00 (SD = 0.89). The heritability of sleep duration was 39% and the Singh Index was 12%. The uncontrolled phenotypic regression of sleep duration on the Singh Index showed a significant negative relationship between area-level deprivation and sleep length (b = -0.080, P < 0.001). Every 1 SD in Singh Index was associated with a ∼4.5 min change in sleep duration. For the quasi-causal bivariate model, there was a significant main effect of E (b(0E) = -0.063; standard error [SE] = 0.30; P < 0.05). Residual variance components unique to sleep duration were significant for both A (b(0Au) = 0.734; SE = 0.020; P < 0.001) and E (b(0Eu) = 0.934; SE = 0.013; P < 0.001)., Conclusions: Area-level deprivation has a quasi-causal association with sleep duration, with greater deprivation being related to shorter sleep. As area-level deprivation increases, unique genetic and nonshared environmental residual variance in sleep duration increases., (© 2016 Associated Professional Sleep Societies, LLC.)

Background: Herpes simplex virus type 2 (HSV-2) genital lesion recurrence is modulated by psychological factors, but no such link with viral shedding (and thus asymptomatic transmission) has been observed in humans., Purpose: The moderating effects of average psychological distress, emotional stability, and emotion regulation on HSV-2 recurrence were tested., Methods: Nineteen HSV-2 seropositive women were followed over 22 weeks. Daily measures of HSV-2 recurrence and psychological distress were collected. HSV-2 lesions and viral shedding were modeled as linear oscillator systems, with psychological distress moderating the periodicity of each process., Results: High levels of distress, more labile moods, and less ability to regulate emotional states were associated with fewer days elapsed between the onset of lesion episodes. Viral shedding showed the same pattern., Conclusions: Results are consistent with research indicating that psychological distress suppresses immune system functioning, and provide new evidence that genital HSV-2 viral shedding is related to, and regulated by, psychological distress.

This study demonstrated that traits and features associated with several types of personality disorders are related to work performance and the ability to conform to requirements of military life. The Schedule for Nonadaptive and Adaptive Personality and a peer nomination procedure were used to assess traits associated with 10 types of personality disorders in a sample of 1,080 Air Force recruits (57% male) at the end of basic military training. Correlations between self-report and peer nomination scores for each set of traits ranged from 0.24 to 0.13, indicating only modest convergence. Follow-up data, collected 2 years later, indicated that several scores from the Schedule for Nonadaptive and Adaptive Personality and the peer nomination procedure were significantly related to early discharge from the military. Peers provide useful information that is not redundant with that provided by the individual. When possible, assessment of personality problems should be considered from information obtained from peers or other informants.