Nov. 30, 2010 — Tricyclic antidepressants have been linked to an increased risk of heart disease in a new study of nearly 15,000 people in Scotland.

Researchers from University College London found that tricyclic antidepressants, an older class of antidepressant, were associated with a 35% increased risk of CVD (cardiovascular disease), but that there was no increased risk with newer antidepressants such as the selective serotonin reuptake inhibitors (SSRIs).

Until now, the researchers say, there have been uncertain and conflicting findings about the risks.

The Study

14,784 men and women without a known history of CVD were studied using data from the Scottish Health Survey.

The researchers combined data from separate surveys in 1995, 1998, and 2003 in adults over 35 and linked them with records on hospital admissions and deaths, with follow-up until 2007.

Anyone with a history of clinically confirmed CVD was excluded.

During the surveys, interviewers visited the homes of participants and asked questions about their lifestyle, such as smoking, alcohol intake, and exercise. Height and weight were recorded and psychological distress was checked using a questionnaire.

In a separate visit, nurses collected medical history information including psychiatric hospital admissions and medications, and took blood pressure readings.

The Results

Over an average of eight years there were 1,434 cardiovascular events, and just over 26% were fatal.

Of the study participants, 2.2% reported taking tricyclic antidepressants, 2% SSRIs, and 0.7% other antidepressants.

After adjusting for various factors, the researchers found there was a 35% increased risk of CVD associated with tricyclic antidepressants.

The use of SSRIs was not associated with any increased risk of CVD, nor did the researchers find any significant associations between antidepressant use and deaths from any cause.

Don’t Stop Taking Medication

The study is the first to contain a representative sample of the whole community, including elderly and unemployed participants, men and women.

The researchers say it is important for people already taking tricyclic antidepressants not to stop taking the medication as a result of this study, but to see their GP if they are worried.

Mark Hamer, PhD, senior research fellow in the department of epidemiology and public health at University College London, tells WebMD, “People who are treated for depression tend to be on the newer ones: SSRIs or even the newer generation.”

However, some patients, for reasons such as intolerance to other treatments, are still prescribed the older types, but Hamer says it isn’t just depression that tricyclic antidepressants are used for: “They are also being used to treat headache, migraine, and tension-related headaches as well.

“There should be some concern about whether they should be using them in the first place.”

Do doctors take enough time to look at the patient’s overall health, not just depression? Hamer says, “That’s a big problem in this area. Mental health and physical health are seen quite separately. We know from our research that the two are very closely linked together.

“A lot of patients with mental health problems also have lots of risk factors for heart disease: They tend to be quite heavy smokers and they don’t exercise. Those sorts of lifestyle factors could be quite easily addressed.”

Reaction

In a statement, Amy Thompson, senior cardiac nurse at the British Heart Foundation, says, “The results of this research should be interpreted with caution. The study wasn’t originally set up to assess the effect of anti-depressants on heart disease risk, but it raised some questions.

“We know that findings like these can turn out to be red herrings, so before firm conclusions can be drawn there needs to be more research looking closely at the effects of these drugs on your heart.”

She agrees with Hamer that people with depression are more likely to have unhealthy lifestyle habits. “By addressing these lifestyle factors you can lower your risk of heart disease and help keep your heart healthy,” she says.

The study is published online in the European Heart Journal.