Social integration and inflammation in individuals with and without posttraumatic stress disorder.

BACKGROUND: Posttraumatic stress disorder (PTSD) is associated with increased risk for morbidity and mortality, which may be mediated through elevated inflammation. In contrast, social support appears to protect against morbidity and mortality, reduce levels of inflammation, and improve PTSD outcomes. METHODS: We examined relationships among social isolation, perceived social support, and inflammation in Veterans Affairs (VA) patients with and without PTSD. Our sample included 735 (35% PTSD+) participants from the Mind Your Heart Study (mean age = 58 ± 11; 94% male). Social isolation was assessed with the Berkman Syme Social Network Index; perceived social support with the Multidimensional Scale of Perceived Social Support; and PTSD with the Clinician Administered PTSD Scale. Inflammation was indexed by high sensitivity C-reactive protein, white blood cell count, and fibrinogen. Hierarchical linear regression was used to examine associations between social measures and inflammation. PROCESS was used to examine the interactive effects of social relationships and PTSD on inflammation. RESULTS: Social isolation, but not low perceived social support, trended towards an association with elevated inflammation in the full sample. However, considering groups with and without PTSD separately, social isolation was significantly associated with all inflammatory markers among individuals without PTSD, but not among those with PTSD. CONCLUSIONS: Social integration is associated with reduced inflammation in individuals without, but not with, PTSD. Socially integrated individuals with PTSD did not have lower levels of inflammatory markers than socially isolated individuals with PTSD.

Longitudinal association of PTSD symptoms and self-reported physical functioning among Veterans.

BACKGROUND: Few longitudinal studies have investigated the potentially dynamic relationship between Posttraumatic Stress Disorder (PTSD) and physical functioning, and the number of follow-up timepoints have been limited. We evaluated whether PTSD symptoms predicted future physical functioning and vice versa using five assessments over four years. METHODS: Data was used from a longitudinal cohort of 695 participants recruited from Veteran Affairs medical outpatient clinics who experienced a traumatic event. PTSD symptom severity was assessed annually with the PTSD Checklist (PCL). Physical functioning was measured with the 10-item subscale of the SF-36. An autoregressive cross-lagged panel model was used to determine the temporal associations between PTSD and physical functioning, adjusting for age, sex, ethnicity, education and employment. Comorbidities and health behaviors were added to assess their roles in the relationship. RESULTS: Greater PTSD symptom severity predicted worse physical functioning the following year (average ß = -0.10, P <0.001), where a 10-point increase in PCL score predicted a 0.3-point decline in physical function score over one year. Similarly, better physical functioning also predicted reduced PTSD severity the following year, but to a smaller magnitude (average ß = -0.04, P = .003). The pattern of effects was similar after controlling for comorbidities and health behaviors. LIMITATIONS: Both primary variables relied on self-report, and generalizability may be limited by the mostly male Veteran sample. CONCLUSIONS: Our results support a bidirectional, but unequal, relationship between PTSD and physical functioning over time. They also highlight the importance of long-term control of PTSD symptoms in preventing functional decline.

Current posttraumatic stress disorder and exaggerated threat sensitivity associated with elevated inflammation in the Mind Your Heart Study.

OBJECTIVE: Elevated inflammation has been repeatedly observed in posttraumatic stress disorder (PTSD), and it may drive the development of both psychiatric symptoms and physical comorbidities. However, it is not clear if elevated inflammation is a feature of both remitted and current PTSD, and little is known about relationships between specific clusters of PTSD symptoms and inflammation. Exaggerated threat sensitivity, as indexed by threat reactivity and avoidance of perceived threats, may be particularly closely associated with inflammation. METHODS: We assessed PTSD symptoms and threat sensitivity using the Clinician Administered PTSD Scale in 735 Veterans Affairs patients (35% current PTSD; 16% remitted PTSD) who participated in the Mind Your Heart Study (mean age=59±11; 94% male). High sensitivity C-reactive protein (hsCRP), white blood cell count (WBC), and fibrinogen were used as indices of inflammation. Analysis of covariance models with planned contrasts were used to examine differences in inflammation by PTSD status, adjusting for age, sex, race, kidney function and socioeconomic status. RESULTS: Individuals with current PTSD had significantly higher hsCRP and WBC than patients with no history of PTSD, but there were no significant differences in inflammatory markers between those with remitted versus no history of PTSD. Within patients with current PTSD, higher threat reactivity was independently associated with higher hsCRP (ß=0.16, p=0.01) and WBC count (ß=0.24, <0.001), and higher effortful avoidance was associated with higher fibrinogen (ß=0.13, p=0.04). CONCLUSION: Our data indicate that elevated inflammation may be a feature of current, but not remitted, PTSD. Within patients with PTSD, higher threat reactivity was also associated with elevated inflammation. A better understanding of the relationship between threat sensitivity and inflammation may inform interventions for patients with PTSD.