The use of medications that have suicidal symptoms as potential side effects also increased, to 23.5 percent of the population in 2013-14, up from 17.3 percent in 2005.
Among patients using one drug that could cause depression as a side effect but who were not taking an antidepressant drug, 6.9 percent had depression, while the depression rate for patients taking three or more drugs with the side effect was 15.3 percent. By contrast, patients who were not taking any such drugs had a depression rate of 4.7 percent.
The researchers adjusted for other risk factors that can cause depression, including poverty, marital status, unemployment and certain medical conditions, like chronic pain, which themselves are associated with depression.
“The study is an important reminder that all medicines have risks, and most medicines have rare but serious risks — yet another reason that even commonly used medicines such as beta-blockers or proton pump inhibitors should not be used cavalierly,” said Dr. Caleb Alexander, co-director of the Center for Drug Safety and Effectiveness at Johns Hopkins Bloomberg School of Public Health, who was not involved in the study.
Dr. Philip R. Muskin, a professor of psychiatry at Columbia University Medical Center and secretary of the American Psychiatric Association, said physicians must keep these side effects in mind when prescribing medications, and ask patients about whether they have a personal or family history of depression.
But he said it is hard to say whether the increased use of drugs, and combination of drugs with side effects including depression, has had an impact on society.
“There’s been an increase in suicide, that we know,” Dr. Muskin said. “Does it correlate to the use of these medications? The honest answer is we don’t know. Could it play a role? The honest answer is yes, of course it could.”