High blood pressure is more common among individuals with posttraumatic stress disorder (PTSD). But new research suggests that not all PTSD symptoms are associated with an increased risk hypertension.

The study, which appears in the journal Psychological Medicine, indicates that fear-related symptoms are the primary driver of elevated cardiovascular risk.

“A growing body of research indicates that PTSD is associated with increased risk of developing a range of cardiovascular conditions, including high blood pressure. However, we don’t know what aspects of PTSD are driving these associations,” said study author Jennifer A. Sumner, an assistant professor of behavioral medicine at Columbia University Medical Center.

“PTSD is a heterogeneous disorder. Indeed, there are 636,120 ways to have PTSD based on the DSM-5 criteria. PTSD can be broadly thought of as having dimensions of fear (an alarm response to real or perceived danger) and dysphoria (low positive affect and loss of interest or pleasure), and we were interested in examining how these dimensions of PTSD related to developing high blood pressure, a major and modifiable risk factor for cardiovascular disease.”

The researchers examined data from the Nurses’ Health Study II, a longitudinal study of 116,429 female US nurses that started in 1989. They zeroed in on 2,709 women who had been exposed to trauma, and were free of hypertension and cardiovascular disease at the time of the traumatic event. Over the course of the study, 925 women developed hypertension.

“In women who had been exposed to a wide range of traumatic events (e.g., sudden and unexpected death of a loved one, unwanted sexual contact, physical assault, miscarriage or stillbirth), we found that elevated fear-related symptoms of PTSD (and not dysphoria-related symptoms of PTSD) were associated with an increased risk of developing high blood pressure,” Sumner explained to PsyPost.

“Fear-related symptoms of PTSD included reports of intrusive thoughts, active avoidance of trauma reminders, hypervigilance, and exaggerated startle. Our findings suggest that fear symptoms associated with PTSD may be a critical driver of elevated cardiovascular risk in trauma-exposed individuals.”

The study controlled for factors such as socio-demographics and parental history of hypertension. However, all research includes some limitations — and the current study is no exception.

“One limitation of this study is that we assessed trauma exposure and PTSD symptoms retrospectively. In addition, we relied on self-reported diagnoses of high blood pressure, although self-reported hypertension has been validated in this cohort (the Nurses’ Health Study II),” Sumner said.

“Generalizability of our findings may also be limited as the Nurses’ Health Study II cohort is all female, predominantly white, and highly educated. Thus, our findings need to be replicated in more diverse samples.”

Some trauma-exposed individuals do not meet criteria for PTSD, but still have an elevated fear response. The new findings suggest that these individuals could still see protective health benefits from therapy.

“A key question for future work is to examine if intervening to reduce posttraumatic manifestations of fear can have a positive impact on maintaining healthy blood pressure levels,” Sumner added.

The study, “Not all posttraumatic stress disorder symptoms are equal: fear, dysphoria, and risk of developing hypertension in trauma-exposed women“, was authored by Jennifer A. Sumner, Laura D. Kubzansky, Andrea L. Roberts, Qixuan Chen, Eric B. Rimm, and Karestan C. Koene.