The large-scale research project analyzed 14 years of medical registry data of more than a million Danish adolescent girls and women age 15 to 34 who had no prior diagnosis of depression.
All types of hormonal contraceptives were positively associated with subsequent use of antidepressants, according to the study published in JAMA Psychiatry on Sept. 28, 2016. But women taking a combined pill — containing both estrogen and a progestin — were 23 percent more likely to be prescribed an antidepressant than women not on hormonal contraception. Women taking progestin-only pills were 34 percent more likely to be prescribed antidepressants.
Adolescent girls were the highest risk group: Those taking progestin-only pills were twice as likely and those taking a combined version were 80 percent more likely to be prescribed antidepressants than their peers not using birth-control.
While women are roughly twice as likely to suffer from depression than men, rates are similar before puberty, and women’s naturally fluctuating levels of hormones, particularly progesterone, have been implicated as a possible cause.
“Our data indicate that adolescent girls are more sensitive than older women to the influence of hormonal contraceptive use on the risk for first use of antidepressants or first diagnosis of depression,” the study authors write. “This finding could be influenced by attrition of susceptibility, but also that adolescent girls are more vulnerable to risk factors for depression.”
If you’re taking oral contraception, don’t despair. While the study raises important questions about an association between depression and hormonal contraception use, it doesn’t indicate causation. Further studies are needed to determine whether or not depression might be a potential side effect of birth-control use.