Oestrogen fluctuations may be an important factor in the etiology of bipolar disorder and age at menarche is associated with the clinical course of BD. Moreover, it is associated with traits related to mood.

The aim of our study was to explore the differences in age at menarche between euthymic BD patients and healthy controls, as well as to explore the relationship between age at menarche and lifetime psychopathology within BD.

The study group consisted of 83 patients diagnosed with BD, compared to the healthy control group (n = 73) and matched according to age, gender, and body mass index (BMI). Lifetime psychopathology has been assessed according to predominant polarity as well as previous history of suicide attempts and psychotic episodes.

Age at menarche in BD patients was similar to that in controls. After covarying for confounders, we observed that age at menarche is negatively related to number of previous depressive episodes in euthymic BD patients, but not other indicators of lifetime psychopathology.

BD patients with earlier age at menarche are more likely to present with more depressive episodes in the course of illness. Systemic, longitudinal monitoring of the course of illness, and potential hormonal fluctuations within particular groups of patients are warranted.

The authors have not supplied their declaration of competing interest.