A recent study by a team at Massachusetts General Hospital found that anxiety and depression can significantly increase the risk of developing potentially life-threatening blood clots, including deep vein thrombosis (DVT).
A DVT can restrict blood flow in the affected vein and raise pressure in the veins. The danger increases if part or all of the clot breaks loose and travels to the lungs, where it can block blood flow and cause shortness of breath, chest pain, or even death.
Over the past decade, researchers have frequently examined the link between mental health and the risk of clot formation. Conflicting study results and complicating factors—such as participants’ use of medications and the presence of hypertension—have made it hard to understand how the two are connected.
In their new study, the medical team looked not only at how much anxiety or depression can elevate DVT risk but also at why this happens.
“My research is based on data from my patients,” said Dr. Rachel Rozovsky, the lead author and director of thrombosis research in the hematology department, in an interview with Live Science. When she noticed a connection between prolonged anxiety and depression and blood clots in her patients, she hypothesized that these mental states could contribute to the development of thrombosis.
How the Study Was Conducted
To investigate this connection, the researchers retrospectively analyzed data from approximately 119,000 individuals. This dataset included measurements of brain activity related to stress obtained through positron emission tomography (PET).
The researchers compared activity in the amygdala—a brain region that responds to perceived threat—with activity in the ventromedial prefrontal cortex, which helps regulate the amygdala and control emotional responses. That comparison gave them a snapshot of stress-related neural activity (SNA).
The data also included measurements of high-sensitivity C-reactive protein, a marker of inflammation, and heart rate variability, a marker of autonomic adaptability. Higher heart rate variability indicates better ability to cope with stressful situations.
Within the cohort, about 106,450 participants were diagnosed with an anxiety disorder and 108,790 with depression. Many participants had both conditions.
Over a period of 3.6 years, roughly 1,780 participants experienced deep vein thrombosis. Those with a history of anxiety and those with a history of depression had a 53% and 48% higher likelihood, respectively, of developing DVT compared with participants without either condition.
Among the 1,520 individuals who underwent PET scans, people with anxiety or depression showed higher levels of SNA than those without those conditions. Individuals with elevated SNA had a 30% greater risk of developing DVT.
The team also found that stress was linked to increased white blood cell activity—the main driver of inflammation. Previous research has connected that inflammation to an increased tendency for blood to clot.
The team identified three potential mechanisms linking anxiety and depression to deep vein thrombosis: elevated SNA, inflammation, and reduced heart rate variability. The study suggests that higher stress levels correspond to higher DVT risk.
The study’s findings were published in the American Journal of Hematology.
