SAN FRANCISCO – Posttraumatic stress disorder that persists into later life was associated with more than a threefold increased risk of functional disability compared with that of individuals with no history of PTSD, according to a first-of-its-kind national study.
The study included a nationally representative sample of Americans aged 55 years or older. The group consisted of 3,287 participants (mean age, 66 years) in the Collaborative Psychiatric Epidemiology Surveys.
Eighty-eight subjects had been diagnosed with PTSD by DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-IV) criteria before age 55 but no longer met diagnostic criteria for the disorder by age 55. An additional 68 were diagnosed with PTSD before age 55, and the anxiety disorder persisted beyond that age. The remaining 3,131 no-PTSD subjects served as controls.
Dr. Amy Byers
The study endpoint was the presence and degree of disability within the past 30 days as defined by the World Health Organization Disability Assessment Schedule. This instrument evaluates disability in five domains: self-care, mobility, cognition, social, and out-of-role, which is measured by the number of days in the past month a participant was completely unable to work or do their normal activities because of physical or mental problems.
The frequency of any of the WHO disability domains in the 30 days prior to evaluation was 36.9% in the no-PTSD controls, 69.6% in those with PTSD that began and ended before age 55, and 79.7% in those with persistent later-life PTSD, according to Amy L. Byers, Ph.D., an epidemiologist in the psychiatry department at the University of California, San Francisco.
In a multivariate analysis adjusted for demographics, comorbid medical conditions, depression, generalized anxiety disorder, substance use disorders, and smoking, study participants with persistent PTSD beyond age 55 were 3.2-fold more likely to have any form of disability than controls. This sharply increased risk extended to each of the five domains of disability. The group with PTSD diagnosed before age 55 but without PTSD after age 55 had a statistically nonsignificant 1.99-fold increased risk. Thus, this study shows that persistence of PTSD in later life is a potent predictor of disability independent of other psychiatric issues and medical conditions. The results are clinically relevant and generalizable to the burgeoning population of older Americans.
"These findings suggest that, if left unresolved, PTSD in older adults will have significant functional consequences," Dr. Byers said. "Our study emphasizes the importance of improving the monitoring and treatment of PTSD over the long term."
One possible mechanism for the strong association between persistent later-life PTSD and disability is that exposure to trauma results in dysregulation of the hypothalamic-pituitary-adrenocortical axis, leading to increased glucocorticoid levels and hippocampal degeneration, she surmised (JAMA Psychiatry 2014 March 19 [doi: 10.1001/jamapsychiatry.2014.5]).
The study was funded by the Department of Defense. Dr. Byers reported having no financial conflicts of interest.