It is well established, both in research and everyday real-world experience, that posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) independently can have a huge impact on physical health. There is evidence, for instance, that both are independent “robust risk factors” for the onset of chronic physical illnesses, including musculoskeletal, digestive, and circulatory, say researchers from VA San Diego; University of California, San Diego; VA Center of Excellence for Stress and Mental Health, San Diego; National Center for PTSD, Vermont; VA Connecticut Health Care System, and Yale. However, less is known about how the 2 conditions might synergistically affect physical health and well-being.
In this, the first population-based study of the burden of medical illness associated with PTSD, MDD, and their comorbidity, the researchers examined data from 2,732 participants in the National Health and Resilience in Veterans Study.
Of the participants, 40 had PTSD only, 141 had MDD only, and 60 had both. Among veterans who screened positive for probable PTSD, 47% also screened positive for probable MDD. Among veterans who screened positive for probable MDD, 83% screened positive for probable PTSD.
The participants with PTSD, MDD, or both had substantially greater burden of medical illness compared with that of those participants who had no lifetime history of either condition. Consistent with findings from previous studies, each group had a greater prevalence of a broad range of medical conditions, including cardiovascular, respiratory, neurologic, and chronic pain-related diseases.
However, the study results indicated that comorbid PTSD/MDD was associated with substantially greater medical comorbidity compared with either disorder alone. Veterans with co-occurring PTSD and MDD had higher odds of being diagnosed with migraine, fibromyalgia, and rheumatoid arthritis, for instance, relative to those with MDD alone.
Co-occurring PTSD/MDD was also associated with “markedly worse” cardiovascular health compared with either condition alone. Veterans with PTSD/MDD had more than twice the likelihood of being diagnosed with hypercholesterolemia and hypertension compared with those who had PTSD alone. They had more than double the odds of being diagnosed with heart disease compared with those who had only MDD.
Several factors may account for why PTSD seems to compound risk for pain-related conditions, the researchers say. People with PTSD may have increased attentional bias toward threatening internal stimuli (above and beyond MDD), which may heighten appraisal of pain; they also tend to have higher levels of anxiety sensitivity, which may amplify fear reactivity to pain. Some evidence suggests that the brain region involved in processing the affective component of pain is dysfunctional in PTSD, leading to an exaggerated response.
The associations between PTSD and pain, and PTSD/MDD and cardiovascular risks were noteworthy, the researchers say, because they were found even after “stringently controlling” for relevant covariates, including lifetime trauma exposure; combat veteran status; and alcohol, drug, and nicotine use disorder.
The finding that PTSD/MDD and PTSD were associated with higher levels of somatization is consistent with other research, the researchers note. But they say more research is needed to examine whether somatization increases vulnerability to the development of PTSD and MDD, or whether symptoms arise as a consequence of the disorders.