(NaturalNews) People who take tricyclic antidepressants are at increased risk for a rare group of blood cancers known as non-Hodgkin lymphoma, according to study conducted by researchers from the Institute of Cancer Epidemiology at the Danish Cancer Society, and published in the journal
"Our results indicate an increased risk of non-Hodgkin lymphoma specifically among long-term users of tricyclic antidepressant medications," the researchers wrote. "Given the high prevalence of antidepressant use, this finding warrants additional studies."
The same research team previously found an increased risk for non-Hodgkin
among those who took
in North Jutland County, Denmark, between 1989 and 1996. In the current study, researchers analyzed data on 354,551 residents of the county who were over the age of 29 between 1989 and 2004, this time collecting data on the specific types of antidepressants used. They found that heavy, long-term users of tricyclic antidepressants had a 2.5 times higher risk of developing non-Hodgkin lymphoma than those who did not take antidepressants at all.
No increase in risk was found among those taking selective serotonin reuptake inhibitors (
The researchers noted that the study was not set up to determine whether the antidepressant drugs were actually causing the disease or not. Because tricyclic antidepressants are more often used for patients with severe depression (as opposed to SSRIs, which are often a first resort), they might merely function as a marker for serious mood disorders, the researchers said. This, in turn could be correlated with a depressed immune system, or with a risky behaviors that are more likely to expose people to the viruses that might cause non-Hodgkin lymphoma.
"Our study, however, raises the hypothesis of a serious long-term side effect from tricyclic antidepressants, and this needs further research," lead researcher Susanne Oksbjerg Dalton said.
The rates of non-Hodgkin lymphoma have more than doubled in Denmark since the 1970s.