Effective management of depression through psychological therapy is associated with a lower likelihood of heart disease and stroke, according to research published today in European Heart Journal, a journal of the European Society of Cardiology (ESC).
“Our study suggests that improving mental health could also help physical health, especially in those aged under 60,” said study author Ms. Céline El Baou, a PhD student at University College London, UK. "People whose depression symptoms improved after therapy had a 10% to 15% lower risk of cardiovascular disease than those who did not improve. Comparable effects were found in similar studies investigating low fat diets."
This was the first study to investigate whether reducing depression symptoms with psychological therapy is associated with a lower likelihood of future cardiovascular disease. The study included 636,955 adults over 45 years old with depression who had completed a course of psychological therapy and did not have cardiovascular disease or dementia. The average age was 55 years and 66% were women. Information on psychological treatment, incidence of cardiovascular disease and death was obtained from national electronic health record databases in England and linked at the individual level.
Depression level was assessed before and after therapy using the Patient Health Questionnaire-9 (PHQ-9) which gives a score of 0 (not at all) to 3 (nearly every day) for nine items including little interest or pleasure in doing things; feeling down, depressed, or hopeless; trouble falling or staying asleep, or sleeping too much; feeling tired or having little energy; poor appetite or overeating; feeling you are a failure or have let yourself or your family down; trouble concentrating on things; moving or speaking slowly or being fidgety or restless; thoughts that you would be better off dead, or of hurting yourself in some way. Depression was defined as a score of 10 or more.
Improvement in depression was defined as a reduction of 6 points or more in the PHQ-9 score and no worsening of anxiety (defined as an increase of 4 points or more on the Generalized Anxiety Disorder scale) between the start and end of treatment. Anxiety was included in the definition so that the outcome of therapy was not considered good if depression improved but anxiety worsened.
Patients were followed for new onset all-cause cardiovascular disease, coronary heart disease, stroke and all-cause mortality. Follow up commenced 365 days after the last therapy session and those with a cardiovascular event during this period were excluded to reduce the likelihood that previously undiagnosed disease was the cause of depression.
During a median follow up of 3.1 years, depression symptoms improved in 373,623 (59%) participants and did not improve in 263,332 (41%). There were 49,803 cardiovascular events and 14,125 participants died. Improvement of depression was associated with 12%, 11%, 12% and 19% lower risks of any cardiovascular disease, coronary heart disease, stroke and all-cause mortality, respectively, versus no improvement. The analyses were adjusted for characteristics that could influence the relationships such as age, ethnicity, gender, socioeconomic deprivation and other health conditions.
All associations were stronger in 45 to 60 year-olds, for whom depression improvement was linked with a 15% fall in the risk of cardiovascular disease compared to no improvement; the equivalent figure for those 60 years and over was 6%. In addition, 45 to 60 year-olds with improved depression had a 22% decreased likelihood of death during follow up compared to not improving, while those 60 and over had a 15% reduction. Ms. El Baou said: “The findings are consistent with previous research suggesting that interventions to modify risk factors for cardiovascular disease are more effective at a younger age. This highlights the value of receiving help early to gain the most benefit.”
The authors noted that the results do not definitively prove that reductions in cardiovascular disease were caused by relief of depression. In addition, data were missing on lifestyle behaviours such as smoking and inactivity which could raise susceptibility to cardiovascular disease and limit the effect of psychological treatment.
Ms. El Baou said: “Our findings emphasise the importance of making psychological treatments more widely available and accessible to enhance mental and physical health. This is especially relevant for certain groups who face barriers to accessing psychological therapies and are at greater risk of cardiovascular disease. Collaborative care systems where specialists from both disciplines work together could be one way to make treatment more accessible and obtain better outcomes overall.”
