Antidepressants linked to non-Hodgkin lymphoma

Long-term users of so-called tricyclic antidepressants are at increased risk of non-Hodgkin lymphoma (NHL), new research confirms.

“We previously reported an increased incidence of NHL among long-term users of tricyclic antidepressant medication in a population-based cohort of more than 30,000 users of antidepressant medications,” Dr. Susanne Oksbjerg Dalton, of the Danish Cancer Society, Copenhagen, and colleagues point out.

Another population-based study did not confirm these findings, but “it did suggest a possible excess of NHL with tricyclic antidepressant medication among the long-term users,” they also note.

In the July issue of Epidemiology, Dalton’s group reports an update of their population-based cohort, increasing the sample size to the entire population of 354,551 adults in North Jutland County. Between 1989 and 2003, the researchers compared the incidence of NHL among antidepressant users and nonusers.

Of the 43,932 subjects who used any antidepressant medications, 11,958 used tricyclic antidepressants, 22,695 used another type of antidepressant known as selective serotonin reuptake inhibitors (SSRIs), 4421 used other antidepressants, and 4858 used more than one type.

There were 92 cases of NHL and, according to the team, there was a strong association between use of tricyclic antidepressants and NHL. No increased risk of NHL was found in users of other types of antidepressants.

“Given the high prevalence of antidepressant use, this finding warrants additional studies with sufficient power to investigate risk by type and dosage of antidepressant medication as well as by lymphoma subgroups,” the researchers conclude.

SOURCE: Epidemiology, July 2008.