Posttraumatic stress disorder (PTSD) and stress/trauma exposure are cross-sectionally associated with advanced DNA methylation age relative to chronological age. However, longitudinal inquiry and examination of associations between advanced DNA methylation age and a broader range of psychiatric disorders is lacking. The aim of this study was to examine if PTSD, depression, generalized anxiety, and alcohol-use disorders predicted acceleration of DNA methylation age over time (i.e. an increasing pace, or rate of advancement, of the epigenetic clock).

Genome-wide DNA methylation and a comprehensive set of psychiatric symptoms and diagnoses were assessed in 179 Iraq/Afghanistan war veterans who completed two assessments over the course of approximately 2 years. Two DNA methylation age indices (Horvath and Hannum), each a weighted index of an array of genome-wide DNA methylation probes, were quantified. The pace of the epigenetic clock was operationalized as change in DNA methylation age as a function of time between assessments.

Analyses revealed that alcohol-use disorders (p = 0.001) and PTSD avoidance and numbing symptoms (p = 0.02) at Time 1 were associated with an increasing pace of the epigenetic clock over time, per the Horvath (but not the Hannum) index of cellular aging.

This is the first study to suggest that posttraumatic psychopathology is longitudinally associated with a quickened pace of the epigenetic clock. Results raise the possibility that accelerated cellular aging is a common biological consequence of stress-related psychopathology, which carries implications for identifying mechanisms of stress-related cellular aging and developing interventions to slow its pace.

To determine the prevalence of mental disorders in a nationally representative sample of protective services workers (PSWs), compare it to that of adults in other occupations, and determine if an association exists between trauma exposure and 3-year incident psychiatric disorders in PSWs.

Data from the longitudinal US National Epidemiologic Survey on Alcohol and Related Conditions waves 1 (fielded 2001-2002) and 2 (fielded 2004-2005) were used to compare the prevalence of mental disorders at baseline in a representative sample of PSWs to that of adults in other occupations. Among PSWs, we also explored the association between recent exposure to potentially traumatic events and the development of mood, anxiety, and alcohol-use disorders over a 3-year follow-up period.

At baseline, PSWs had a lifetime prevalence of mental and alcohol-use disorders similar to that of adults in other occupations. However, PSWs experienced a greater variety of potentially traumatic events between baseline and follow-up. Exposure to a greater number of different trauma types was associated with increased odds of incident mood (adjusted odds ratio [AOR] = 1.87, 95% CI = 1.09-3.22, P = .024), and alcohol-use disorders (AOR = 1.84, 95% CI = 1.16-2.91, P = .011). These associations were particularly strong among early career PSWs who joined the profession between waves 1 and 2 (AOR = 2.30, 95% CI = 1.26-4.19, P = .008, for mood disorders; AOR = 2.44, 95% CI = 1.30-4.58, P = .007, for alcohol-use disorders).

While PSWs do not appear to have a higher prevalence of mental health problems than workers in other occupations, they are more likely to experience multiple types of potentially traumatic events. PSWs who are exposed to multiple types of potentially traumatic events are at increased risk of developing new mental disorders, particularly in the early stages of their careers. Developing curricula in coping skills and providing timely interventions for early career PSWs may help reduce future psychiatric morbidity in these workers. (Disaster Med Public Health Preparedness. 2013;7:36-45)