The incidence of depression has been rising in the U.S. for more than a decade. So has Americans’ reliance on prescription medications that list depression as a possible side effect.
Perhaps not, according to a new study in the Journal of the American Medical Assn.
Using 10 years of data collected from more than 26,000 Americans, researchers reported a significant link between the use of medications with the potential to cause depression and the chances of becoming depressed.
For example, among the 4,394 people who took one prescription drug that had depression as a possible side effect, 6.9% experienced depression. Of the 1,418 who took two such drugs, 9.5% became depressed, as did 15.3% of the 710 people who took three or more of the medications.
Meanwhile, the prevalence of depression among the 17,039 who didn’t take any of these medications was 4.7%.
All of these figures were adjusted for age, sex, race and ethnicity, education and job status, family income, body mass index and other health factors, according to the study.
The researchers, led by Dr. Dima Mazen Qato of the College of Pharmacy at the University of Illinois at Chicago, conducted the same analysis with medications that did not list depression as a possible side effect. In this case, the prevalence of depression among those who didn’t take any such drugs (5.5%) was not significantly different statistically from the prevalence for those who took one or more medications not linked to depression. The rates of depression among this group were 6.6% for those taking one drug, 5.1% for those taking two, and 6% for those taking three or more.
The data in the study came from the National Health and Nutrition Examination Survey, a project of the Centers for Disease Control and Prevention. Qato and her team focused on five consecutive survey cycles, starting with the one taken in 2005 and 2006 and ending with the most recent, done in 2013 and 2014. Participants received home visits from interviewers who asked to see all prescription medications they had taken in the previous 30 days.
Researchers then used the Micromedex database to look up side effects for each of the drugs. Of particular interest were “depression,” “depressive disorder,” “suicide,” “suicidal thoughts,” “suicidal ideation” and “suicidal behavior,” the study said.
The researchers tallied more than 200 medications that listed at least one of these side effects. Altogether, 37% — representing more than 1 in 3 Americans — took at least one of the drugs on the list.
Among the most common medications with such side effects were antidepressants (taken by 15.1% of participants in the study’s most recent years), gastrointestinal agents to treat conditions like acid reflux (taken by 9.5% of study participants), beta blockers for high blood pressure (taken by 7.9% of participants), hormones used to prevent pregnancy or treat symptoms of menopause (taken by 7.8% of participants), anticonvulsant drugs (taken by 7.7% of participants) and prescription pain relievers (taken by 7.4% of participants).
In the earliest years of the study, 6.9% of people used at least three drugs that listed depression as a possible side effect. By the end of the study period, that figure had risen to 9.5% — a difference that was large enough to be statistically significant.
In addition, the proportion of people who took at least one drug that listed suicidal symptoms as a possible side effect rose from 17.3% to 23.5% over the course of the study. That increase was also statistically significant.
The researchers conducted a separate analysis that excluded people taking antidepressants. Even then, depression was found in 8.5% of those taking three or more drugs with the potential to cause it, compared with 4.5% of those who took no such drugs, according to the study.
The survey data did not include information on participants’ mental health histories, so the study’s authors could not take that into account. Nor could they tell whether people had used over-the-counter medications that could have depression as a side effect, among other limitations.
Still, the findings fit with other recent studies that have linked the use of proton pump inhibitors or oral contraceptives with increased odds of depression. They do not show that prescription medications are responsible for an increase in depression — only that there is a correlation between the two.
That should prompt doctors and patients to be mindful of the potential side effects of common prescription drugs, especially if they are taking more than one, the study authors concluded.
“Physicians should consider discussing these associations with their patients who are prescribed medications that have depression as a potential adverse effect,” they wrote.