Depression is a modifiable risk factor associated with cardiovascular disease (CVD), the leading cause of death worldwide. New UK research has shown that treating depression with psychotherapy may decrease the risk of developing CVD in people over 45.
People with CVD experience higher rates of depression than those without. For those diagnosed with a major depressive disorder, the risk of developing CVD is around 72% higher than those without depression.
If depression is a modifiable risk factor for CVD, it makes sense to treat it effectively to reduce that risk. Psychotherapy or ‘talk therapy’ is a way of treating mental illness through discussion, listening, and counseling. But despite the known association between depression and CVD, there is a dearth of evidence regarding the effect psychological therapies have on CVD risk.
Now, researchers have considered how reducing depression symptoms through psychotherapeutic intervention affects the risk of developing CVD. The researchers used the electronic healthcare records of 636,955 UK adults over 45 with depression who’d completed a course of psychotherapy. Participants did not have CVD or dementia. The average age of participants was 55 years and 66% were women.
Participants’ depression levels were measured before and after therapy using the Patient Health Questionnaire-9 (PHQ-9), which scores nine items from zero (not at all) to three (nearly every day). Items include pleasure derived from doing things, feeling down or depressed, trouble sleeping or sleeping too much, low energy levels, and trouble concentrating.
For the purposes of the study, depression was defined as a score of 10 or above on the PHQ-9. Improvement in depression symptoms was defined as a reduction of six or more points in the PHQ-9 score between the start and the end of treatment.
The patients were followed to see if they developed CVD, and if they did, they were excluded from the study to reduce the likelihood that previously undiagnosed CVD was the cause of depression.
After following participants for a median time of just over three years, researchers found that depression symptoms improved in 59% of participants and did not improve in 41%. Compared to those who had no improvement, an improvement in depression score was associated with a 12% lower risk of developing any form of CVD, 11% lower risk for coronary heart disease, 12% lower risk for stroke, and 19% lower risk for all-cause mortality.
All associations were stronger in 45- to 60-year-olds, where depression symptom improvement was linked to a 15% decrease in CVD risk. In addition, this age group, with improved depression scores, had a 22% decreased likelihood of death during follow-up compared to those whose depression scores did not improve. Those over 60 had a 15% reduction.
The researchers say that the magnitude of reduction in CVD risk following psychotherapy is comparable to the effect seen in studies that show how low-fat or low-carb diets modify CVD risk. And they say that their study highlights the need for early mental health intervention.
“The findings are consistent with previous research suggesting that interventions to modify risk factors for cardiovascular disease are more effective at a younger age,” said Céline El Baou, lead author of the study. “This highlights the value of receiving help early to gain the most benefit.”
The researchers note the limitations of their study, namely that lifestyle behaviors such as smoking and inactivity were not included and may raise CVD susceptibility.
While the researchers point out that the study’s findings do not prove definitively that reducing depression symptoms lowers CVD risk, they are positive that making psychotherapeutic treatments available can only help.
“Our findings emphasize the importance of making psychological treatments more widely available and accessible to enhance mental and physical health,” El Baou said. “This is especially relevant for certain groups who face barriers to accessing psychological therapies and are at greater risk of cardiovascular disease.”
The study was published in the European Heart Journal.