Among the patients attending an urban hospital-based primary care practice, PTSD is an exceptionally common diagnosis.51
Almost one-quarter of patients met the criteria for current PTSD and one-third met the criteria for lifetime PTSD. Importantly, documentation of this diagnosis was exceedingly uncommon. Only 11% of those with current PTSD were correctly identified in the medical record. In patients with certain conditions (chronic pain, IBS, depression, anxiety disorder, and SD), PTSD prevalence was two to three times as high; patients with these conditions accounted for over 90% of all cases of PTSD. While over a quarter of those with a co-occurring condition had PTSD, not having a co-occurring condition made the diagnosis of PTSD very unlikely.
Our findings are consistent with the published studies of people with PTSD reporting more physical symptoms.52–58
Multiple factors may contribute to the association between PTSD and physical symptoms including organic illnesses,31,57,59–61
and psychological mechanisms.30
In this study, lifetime PTSD was present in half of patients with current heavy drinking and SD. These findings are similar to those from substance-abuse treatment settings and primary care.38,39,65
Surprisingly, current SD and heavy drinking were strongly associated with lifetime PTSD but only weakly with current PTSD. One explanation may be that substance use dampens PTSD symptoms, an assertion supported by reports of PTSD patient self-medication in other studies.66–68
Another explanation may be that patterns of substance use are initiated in a period of current PTSD but persist beyond its resolution.
The higher PTSD prevalence in those with a diagnosis of depression and anxiety was not unexpected based on the literature detailing the psychiatric conditions comorbid with PTSD.12,69
While primary care clinicians have become relatively more comfortable with identifying and managing depression in the past 10 years, more work remains to optimize screening and treatment for other psychiatric disorders.70–73
More than half of our participants with EMR documentation of depression met the diagnostic criteria for PTSD, suggesting that clinicians may have labeled psychological distress as the more familiar diagnosis of depression.
Unlike depression, for which medication alone can be effective, evidence-based care for PTSD includes psychotherapy with or without medication.74
Trauma-focused psychotherapies can result in significant improvement of symptoms in more than half of patients.75
Thus, treatment by primary care clinicians may require new strategies beyond psychoactive medication prescription. In particular, the close relationship between physical problems and PTSD suggests an avenue to develop new interventions, better coordinating the care of general medicine and mental-health clinicians. Such coordination of care to address mental-health conditions in the primary care setting has been encouraged by a recent Institute of Medicine report.76
Based on this study’s findings, clinicians should consider evaluating patients who present with more than 3 months of physical pain or IBS for PTSD and referring those with PTSD for care. In addition, effective PTSD treatment may improve pain. Extensive literature suggests that treating depressive symptoms can improve pain and disability.77–81
An unexpected finding was the lower PTSD prevalence among immigrants. The study eligibility requirement to speak English likely selected acculturated immigrants, producing a “healthy immigrant effect”.82
Immigrants in this study had more social support as well. Other studies suggest lower psychiatric morbidity among some immigrant groups, depending on home country, socioeconomic status and subsequent adjustment to their adopted land.83
Additionally, it is likely that immigrants with PTSD would have had substantial barriers to learning English fluently enough to participate in this study.84
Future studies should examine both English and non-English speaking immigrants for PTSD to better understand its prevalence.
The prevalence of PTSD in these urban primary care patients was markedly higher than that found in most other studies of primary care settings, including those involving veterans, where PTSD prevalence is expected to be high.14,15,18,19,21,31,37,85
Possible explanations for this population’s high PTSD prevalence are rooted in its socioeconomic profile with high exposure to trauma and low levels of social support. In a recent study of high school students in Boston, 71% witnessed violence and 44% were directly victimized in the prior year.86
Social support is an important source of protection from the development of PTSD after trauma exposure,87–90
and several demographic characteristics can serve as proxies for social support in this study. For example, half of our participants earned less than $20,000 per year. Likewise, half of the participants, all of whom were of working age, were unemployed or disabled. In addition, only 27% were married or living with a partner.91,92
There were limitations to this study. As a diagnostic instrument, the CIDI PTSD module only assessed for symptoms after one trauma selected as most stressful by the participant, whereas other diagnostic interviews assessed for symptoms after multiple traumas, offering more opportunities for PTSD diagnosis. However, the instrument used in this study is the same or very similar to those instruments used in national PTSD studies.12,13
Our sample was drawn from a single hospital care system whose mission is to serve vulnerable populations and may not represent settings with a broader range of patients. However, our sample is similar to other urban medical settings serving low-income populations in demographic characteristics as well as prevalence of: depression, trauma exposure, substance-use disorders, and co-occurring chronic conditions.16,93–97
Further research in primary care settings serving other populations is warranted. Lastly, the prevalence would only apply to patients aged 18–65 years old presenting for care, not to a population of all primary care patients.
Despite these limitations, the study had numerous strengths. We enrolled a large primary care sample of patients, oversampled for less prevalent comorbid conditions of interest, utilized a well-regarded structured diagnostic interview for PTSD, and analyzed data with multivariable approaches. These methodological features address some of the concerns with prior studies of PTSD prevalence in primary care.
Our results underscore the need to focus on the identification and treatment of PTSD in urban primary care settings as well as to explore the relationship between PTSD and certain conditions (chronic pain, IBS, SD, heavy drinking, depression, anxiety, and immigrant status) in varied settings with lower baseline PTSD prevalence. Before recommending broad screening for PTSD, screening tools and interventions in the primary care setting need to be developed and tested. In the meantime, it is appropriate for primary care clinicians treating patients in high-risk areas, particularly those with the conditions identified in this study, to assess for PTSD and refer those identified to effective care.