In addition, the researchers found that the risk of a heart attack and other sudden and severe cardiovascular events is especially high in the 6 months that follow the diagnosis of the stress-related condition.
For other types of cardiovascular disease — such as heart failure, a disease that develops slowly — the risk appears to be highest during the 12 months that follow the psychiatric diagnosis.
For embolism and thrombosis, which are major conditions that develop from blood clots, the risk is likely higher 1 year or more after a diagnosis of stress-induced illness.
In a paper in The BMJ about the study, the authors state that the findings apply “equally to men and women” and do not depend on medical history, family background, or having other psychiatric illnesses.
They also note that the results support those of previous studies on relations between stress-induced conditions and cardiovascular disease.
However, most previous findings have come from research that drew largely on male war veterans or men on active military service, and they also focused almost entirely on PTSD, with symptom data from self-reports.
PTSD and similar stress-induced conditions
Anyone who has witnessed or experienced a traumatic event, such as combat, rape, violent assault, or natural disaster can develop PTSD, which affects around 3.5 percent of adults in the United States.
However, witnessing or experiencing a traumatic event does not necessarily lead to PTSD.
When diagnosing PTSD, doctors look for symptoms such as startled reaction to loud noise, flashbacks, and nightmares, together with feelings of detachment, more-than-usual anger, sadness, and irritability that remain intense and do not wane with time.
In some people, the symptoms of PTSD can last for years.
Acute stress disorder is a similar condition to PTSD; it can occur in response to traumatic events and has some of the same symptoms, but it tends to arise within 3–30 days after the traumatic event.
In the U.S., estimates suggest that 13–21 percent of car accident survivors and up to half of those who survive rape, assault, or mass shootings will develop acute stress disorder. Around half of the people with acute stress disorder go on to develop PTSD.
The study and its key findings
The new investigation used 1987–2013 data from the Swedish National Patient Register on 136,637 patients “with stress-related disorders, including [PTSD], acute stress reaction, adjustment disorder, and other stress reactions.”
The researchers ran comparisons between this “exposed” cohort and two other “unexposed” cohorts, one comprising 171,314 full siblings and the other comprising 1,366,370 matched individuals from the general population. By unexposed, the researchers mean free of stress-related conditions.