Early menarche and adult major depressive disorder among Japanese women: The role of childhood traumatic experience and socioeconomic conditions in young adulthood.

Early menarche was significantly associated with increased risk for depression by the age of 40 years. Childhood trauma and socioeconomic hardship in early adulthood did not account for the association. Both physical and psychosocial risk factors in early life need to be addressed for preventing women's depression.