Researchers have found that a class of older generation anti-depressants is connected to an elevated risk of cardiovascular disease (CVD).
The study that followed nearly 15,000 people in Scotland showed that tricyclic anti-depressants were associated with a 35pc increased risk of CVD, but that there was no increased risk with the newer anti-depressants such as the selective serotonin reuptake inhibitors (SSRIs).
The prospective study led by researchers from University College London (UCL), which followed 14,784 men and women without a known history of CVD, is the first to look at the risks associated with the use of anti-depressants in a large, representative sample of the general population.
Dr Mark Hamer, Senior Research Fellow in the Department of Epidemiology and Public Health at UCL and his colleagues used data from the Scottish Health Survey, which collects information from the general population every three to five years.
They combined data from separate surveys in 1995, 1998 and 2003 in adults aged 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 an average of eight years follow-up there were 1,434 events related to CVD, of which 26.2pc were fatal.
Of the study participants, 2.2pc, 2pc and 0.7pc reported taking tricyclic anti-depressants, SSRIs or other antidepressants respectively.
After adjusting for various confounding factors, including indicators of mental illness, the researchers found there was a 35pc increased risk of CVD associated with tricyclic anti-depressants.
The use of SSRIs was not associated with any increased risk of CVD, nor did the researchers find any significant associations between anti-depressant use and deaths from any cause.
"Our findings suggest that there is an association between the use of tricyclic anti-depressants and an increased risk of CVD that is not explained by existing mental illness," Hamer said.
"This suggests that there may be some characteristic of tricyclics that is raising the risk. Tricyclics are known to have a number of side effects; they are linked to increased blood pressure, weight gain and diabetes and these are all risk factors for CVD," he said.
The study is published online today in the European Heart Journal.