Inclusion and exclusion criteria
Eligible for inclusion in all three studies were women without previous psychiatric diseases or use of antidepressants or psychotropic drugs during a four- or five-year period prior to the study period. Pregnant women were excluded in all three studies. Women with previous thrombosis or cancer were excluded in study 1 and 3 and controlled for in study 2. Study 33 in addition excluded all women having used hormonal contraception before the age of 15 years. The argument was that women starting use of hormonal contraception before 15 years often have medical conditions indicating that use. Study 3 also excluded women who during the study period developed other mental disorders, also if at the same time getting a depression diagnosis.