Nightmares: an independent risk factor for cardiovascular disease?

STUDY OBJECTIVES: Prior work has established associations between post-traumatic stress disorder (PTSD), disrupted sleep, and cardiovascular disease (CVD), but few studies have examined health correlates of nightmares beyond risks conferred by PTSD. This study examined associations between nightmares and CVD in military veterans. METHODS: Participants were veterans (N = 3468; 77% male) serving since September 11, 2001, aged 38 years (SD = 10.4); approximately 30% were diagnosed with PTSD. Nightmare frequency and severity were assessed using the Davidson Trauma Scale (DTS). Self-reported medical issues were assessed using the National Vietnam Veterans Readjustment Study Self-report Medical Questionnaire. Mental health disorders were established using the Structured Clinical Interview for DSM-IV. The sample was stratified by the presence or absence of PTSD. Within-group associations between nightmare frequency and severity and self-reported CVD conditions, adjusting for age, sex, race, current smoking, depression, and sleep duration. RESULTS: Frequent and severe nightmares during the past week were endorsed by 32% and 35% of participants, respectively. Those endorsing nightmares that were frequent, severe, and the combination thereof were more likely to also evidence high blood pressure (ORs 1.42, OR 1.56, and OR 1.47, respectively) and heart problems (OR 1.43, OR 1.48, and OR 1.59, respectively) after adjusting for PTSD diagnosis and other covariates. CONCLUSIONS: Nightmare frequency and severity among veterans are associated with cardiovascular conditions, even after controlling for PTSD diagnosis. Study findings suggest that nightmares may be an independent risk factor for CVD. Additional research is needed to validate these findings using confirmed diagnoses and explore potential mechanisms.

Effects of trauma-focused rumination among trauma-exposed individuals with and without posttraumatic stress disorder: An experiment.

Rumination, or thinking repetitively about one's distress, is a risk factor for posttraumatic stress disorder (PTSD). Current theories suggest that rumination contributes to PTSD symptoms directly, by increasing negative reactions to trauma cues (i.e., symptom exacerbation), or represents a form of cognitive avoidance, if verbal ruminations are less distressing than trauma imagery. The goal of this study was to test the symptom exacerbation and cognitive avoidance accounts of trauma-focused rumination. We recruited 135 trauma-exposed participants (n = 60 diagnosed with PTSD) and randomly assigned them to ruminate about their trauma, distract themselves, or engage in trauma imagery. For individuals with and without PTSD, rumination led to larger increases in subjective distress (i.e., negative affect, fear, sadness, subjective arousal, valence) than distraction, ηp 2 s = .04-.13, but there were no differences between rumination and imagery ηp 2 s = .001-.02. We found no evidence that rumination or imagery elicited physiological arousal, ds = 0.01-0.19, but did find that distraction reduced general physiological arousal, as measured by heart rate, relative to baseline, d = 0.84, which may be due to increases in parasympathetic nervous system activity (i.e., respiratory sinus arrhythmia), d = 0.33. These findings offer no support for the avoidant function of rumination in PTSD. Instead, the findings were consistent with symptom exacerbation, indicating that rumination leads directly to emotional reactivity to trauma reminders and may be a fruitful target in PTSD intervention.

Respiratory sinus arrhythmia reactivity in anxiety and posttraumatic stress disorder: A review of literature.

Respiratory sinus arrhythmia (RSA) reactivity is thought to indicate how adaptively one responds to stress. RSA reactivity has been examined across anxiety disorders and posttraumatic stress disorder (PTSD), to better understand the psychophysiological stress response of these disorders. The current state of the literature is mixed, and the association between RSA reactivity and PTSD/anxiety is unclear. This review examines RSA reactivity in response to laboratory stressor tasks across samples with anxiety and PTSD. Results indicated a complex literature that may suggest an association between anxiety/PTSD and RSA reactivity. There is evidence to suggest a pattern of heightened RSA withdrawal in PTSD and trait anxious samples. There was little evidence to suggest a heightened RSA withdrawal pattern in other anxiety disorders. This review also highlights methodological considerations which may allow for clearer interpretations of RSA reactivity. The current literature includes heterogeneity across stressor tasks, RSA measures, and comorbidities that complicates interpretation of results. Studies using samples with comorbid depression produce more consistent evidence of heightened RSA withdrawal in anxiety/PTSD. Future directions for understanding the contribution of these variables (i.e., stressor tasks, RSA measures, comorbid depression) and mechanisms contributing to the possible association between RSA reactivity and anxiety/PTSD are considered.

Emotion regulation in posttraumatic stress disorder (PTSD): Rumination accounts for the association between emotion regulation difficulties and PTSD severity.

OBJECTIVE: The current study investigated whether rumination accounts for the relationship between multiple aspects of emotion regulation (ER) difficulties and posttraumatic stress disorder (PTSD) severity. METHOD: Participants were 90 community members (43% diagnosed with PTSD; Mage = 26.7, 86% female) who were interviewed using the Clinician-Administered PTSD Scale-5 and completed self-reported measures of ER and rumination. RESULTS: The indirect effect of rumination completely accounted for the relationship between overall ER difficulties and PTSD severity. This finding was replicated for three unique aspects of ER (i.e., nonacceptance of negative emotions, impulse control difficulties under emotional distress, and the ability to maintain goal-oriented behavior under emotional distress). Reverse models testing the indirect effect of ER on the link between rumination and PTSD were nonsignificant. CONCLUSIONS: Rumination is an important cognitive process linking specific aspects of ER difficulties to PTSD. Clinical interventions focused on improving ER abilities among those with PTSD may benefit from targeting rumination.

Resting respiratory sinus arrhythmia and posttraumatic stress disorder: A meta-analysis.

Respiratory sinus arrhythmia (RSA) has been examined as a psychophysiological marker of stress vulnerability. Research indicates that low resting RSA is associated with physical and mental health problems, including posttraumatic stress disorder (PTSD). Some research suggests that people diagnosed with PTSD have lower RSA than people without PTSD, but findings have been mixed and the overall magnitude of this effect is unknown, indicating the need for a comprehensive meta-analysis. This meta-analysis examined the association between PTSD and baseline RSA in 55 studies, including 12 unpublished studies, with a total sample size of 6689. Studies were included if they used a PTSD measure, a baseline measure of RSA, and involved humans. Studies were excluded if they were not available in English, did not present quantitative data, presented duplicate data, were a case series, or did not provide results required for computing an effect size. The meta-analysis indicated there is a small but significant association between PTSD and RSA (g = -0.26; 95% CI = -0.35, -0.16) with moderate heterogeneity. Moderator analyses suggested that effects are larger for adults than for children and for DSM-5 PTSD measures than for non-DSM referenced measures. We found some evidence for publication bias among the meta-analysis findings. Overall, there is a small but reliable association between PTSD and lower resting RSA, providing support for further research examining the complex relationship between parasympathetic activity and PTSD.

Association between perceptions of military service and mental health problems in a nationally representative sample of United States military veterans.

OBJECTIVE: In this study, we examined the prevalence of positive and negative perceptions of military service, associations between these perceptions and other demographic and military-related factors, and the extent to which endorsement of positive and negative perceptions of military service are associated with current mental health problems among United States veterans. METHOD: We analyzed data from the National Health and Resilience in Veterans Study (NHRVS), a nationally representative survey of 1,484 United States military veterans, 564 of which reported combat exposure. We assessed perceptions of the effects of military service using a scale developed by Elder and Clipp (1989). RESULTS: Results showed that desirable effects of service (53.6-86.5%) were more frequently endorsed than undesirable effects (9.5%-48.1%), and that combat-exposed veterans (11.5%-59.7%) were more likely to endorse undesirable effects of service than veterans without combat exposure (4.0%-40.7%). We also found that undesirable effects of service predicted significantly higher odds of probable current mental health disorders (OR = 1.08, 95% CI [1.04, 1.12]), and current suicidal ideation (OR = 1.09, 95% CI [1.05, 1.13]), even after conservative adjustment for possible confounding variables. Desirable effects of service predicted significantly lower odds of current suicidal ideation (OR = 0.96, 95% CI [0.93, 0.99]). CONCLUSION: Taken together, results of this study suggest that perceptions of military service are associated with suicidal ideation and other mental health conditions. In addition, assessing veterans' perceptions of their service could be used as a method to identify possible at-risk veterans who may benefit from mental health services and resources. (PsycINFO Database Record

Heightened sensitivity to emotional expressions in generalised anxiety disorder, compared to social anxiety disorder, and controls.

Few studies have examined potential differences between social anxiety disorder (SAD) and generalised anxiety disorder (GAD) in the sensitivity to detect emotional expressions. The present study aims to compare the detection of emotional expressions in SAD and GAD. Participants with a primary diagnosis of GAD (n = 46), SAD (n = 70), and controls (n = 118) completed a morph movies task. The task presented faces expressing increasing degrees of emotional intensity, slowly changing from a neutral to a full-intensity happy, sad, or angry expressions. Participants used a slide bar to view the movie frames from left to right, and to stop at the first frame where they perceived an emotion. The frame selected thus indicated the intensity of emotion required to identify the facial expression. Participants with GAD detected the onset of facial emotions at lower intensity of emotion than participants with SAD (p = 0.002) and controls (p = 0.039). In a multiple regression analysis controlling for age, race, and depressive symptom severity, lower frame at which the emotion was detected was independently associated and GAD diagnosis (B = -5.73, SE = 1.74, p < 0.01). Our findings suggest that individuals with GAD exhibit enhanced detection of facial emotions compared to those with SAD or controls.

The COOH terminus of the amelogenin, LRAP, is oriented next to the hydroxyapatite surface.

The organic matrix in forming enamel consists largely of the amelogenin protein self-assembled into nanospheres that are necessary to guide the formation of the unusually long and highly ordered hydroxyapatite (HAP) crystallites that constitute enamel. Despite its ability to direct crystal growth, the interaction of the amelogenin protein with HAP is unknown. However, the demonstration of growth restricted to the c-axis suggests a specific protein-crystal interaction, and the charged COOH terminus is often implicated in this function. To elucidate whether the COOH terminus is important in the binding and orientation of amelogenin onto HAP, we have used solid state NMR to determine the orientation of the COOH terminus of an amelogenin splice variant, LRAP (leucine-rich amelogenin protein), which contains the charged COOH terminus of the full protein, on the HAP surface. These experiments demonstrate that the methyl 13C-labeled side chain of Ala46 is 8.0 A from the HAP surface under hydrated conditions, for the protein with and without phosphorylation. The experimental results provide direct evidence orienting the charged COOH-terminal region of the amelogenin protein on the HAP surface, optimized to exert control on developing enamel crystals.