Depression and hormonal contraception

• In this article, we will introduce results of scientific studies that have analyzed the association between hormonal pregnancy contraception and depression or other mood disorders.
• First, two large cohorts, one from Denmark «Skovlund CW, Mørch LS, Kessing LV ym. Association ...»1 and one from Sweden «Lindberg M, Foldemo A, Josefsson A ym. Differences...»2, will be introduced.
• Then, a brief summary of other, smaller studies will be given.

A summary of the study by Skovlund et al. (2016) «Skovlund CW, Mørch LS, Kessing LV ym. Association ...»1

• A large Danish prospective cohort of all 15 to 34 year old women who lived in Denmark between 2000 and 2013 (1 061 997 women in total).
• Exclusion criteria:
  • Before entering study: diagnosis of depression, antidepressant medication, psychiatric illness, cancer, venous thrombosis or fertility treatment.
  • Moved to Denmark after 1995
• Endpoints:
  • Starting first antidepressant medication
  • First diagnosis of depression
• Confounding factors acknowledged:
  • Age
  • Level of education
  • PCO and endometriosis
  • BMI (available for only part of women)
  • Smoking (yes or no, available for only part of women)
• Data sources: The National Prescription Register, Psychiatric Central Research Register, Statistic Denmark, National Health Register, National Birth Register
• Results:
  • 55.5% of women used or had used hormonal contraception
  • 133 178 women started their first antidepressant medication during study period
  • Absolute risks: no hormonal contraception = 1.7%/yr; combined hormonal comtraception = 2.1%/yr (NNH = 250); progestin-only contraception = 2.5%/yr (NNH = 125)
  • 23 077 women were diagnosed with depression for the first time during study period
    • Absolute risks: no hormonal contraception = 0.31%/yr; combined hormonal contraception = 0.34%/yr (NNH = 3 333); progestin-only contraception = 0.40%/yr (NNH = 1 111)
• Risk ratios, when adjusted for age, calendar year, educational level, PCO and endometriosis (compared to those who did not use hormonal contraception)
  • Antidepressant medication:
    • Combined hormonal contraception RR 1.2 (CI 1.22 – 1.25)
    • Progestin-only contraception RR 1.3 (CI 1.27 – 1.40)
  • Diagnosis of depression:
    • Combined hormonal contraceptives RR 1.1 (CI 1.08 – 1.14)
    • Progestin-only contraception RR 1.2 (CI 1.04 – 1.31)
  • There seemed to be differences between products.
  • Young women (aged 15 to 19) had the biggest risks.
• The strength of the study is that the exposure (hormonal contraception) has come before the first antidepressant medication or depression treatment, and therefore the association has been possible to analyze.
• The limitation of the study is that not all confounding factors could be addressed, and therefore no definite conclusions on the causal relationship may be drawn.

A summary of the study by Lindberg et al. (2016) «Lindberg M, Foldemo A, Josefsson A ym. Differences...»2

• A large Swedish cohort «Lindberg M, Foldemo A, Josefsson A ym. Differences...»2 (N = 917 993), which analyzed the prevalence of antidepressant medication and diagnosis of depression in women who either do or do not have hormonal contraception. Confounding factors other than age could not be accounted for.
• Therefore, the research setting is remarkably weaker than that of the Danish study introduced above «Skovlund CW, Mørch LS, Kessing LV ym. Association ...»1.
• The results in the younger age group (16 to 19 years of age) were in line with those of the Danish study «Skovlund CW, Mørch LS, Kessing LV ym. Association ...»1.

Other, smaller studies

• In addition to the two large studies introduced above «Skovlund CW, Mørch LS, Kessing LV ym. Association ...»1, «Lindberg M, Foldemo A, Josefsson A ym. Differences...»2, several smaller studies have been performed.
  • The results of these differ from each other, and no reliable conclusions may be drawn from them.
• Two Finnish studies suggested that hormonal contraception does not affect mental well-being «Toffol E, Heikinheimo O, Koponen P ym. Hormonal co...»3 or that women using combined hormonal contraception have less depression as compared to non-users «Toffol E, Heikinheimo O, Koponen P ym. Further evi...»4.
• International studies from western countries havesuggested that users of hormonal contraception have less depressions and anxiety than non-users «Cheslack-Postava K, Keyes KM, Lowe SR ym. Oral con...»5, «Keyes KM, Cheslack-Postava K, Westhoff C ym. Assoc...»6, or that their mood does not differ from that of non-users «O'Connell K, Davis AR, Kerns J. Oral contraceptive...»7, «Duke JM, Sibbritt DW, Young AF. Is there an associ...»8.
• In one Australian study «Duke JM, Sibbritt DW, Young AF. Is there an associ...»8 women, who used hormonal contraception for reasons other than contraception, had more depressions than their comparisons.
• One American study «Joffe H, Cohen LS, Harlow BL. Impact of oral contr...»9 suggested that previous depression was the most significant risk factor for combined hormonal contraception users to have adverse effects on mood.