The bidirectional relationship between vasomotor symptoms and depression across the menopausal transition: a systematic review of longitudinal studies.

OBJECTIVE: To explore the nature of the bidirectional relationship between vasomotor symptoms (VMS) and depression, and to determine whether hot flashes and night sweats differentially affect the association between VMS and depression through their effect on sleep disruption. METHODS: Multiple databases were searched from 1961 until July 31, 2016, and a manual search of reference lists of identified articles was conducted. Sixteen articles that involved 10,008 participants were identified and analyzed. RESULTS: The methods of analyses and measurement of VMS and depression varied across the studies. Two studies explored the bidirectional association, but only one was significant in both directions (odds ratio [OR] depression to VMS 3.06, 95% confidence interval [CI] 1.43-6.58; OR VMS to depression 8.88, 95% CI 2.57-30.68). In both cases, the association between VMS leading to depressive symptoms was stronger than the opposite. Eleven studies examined VMS leading to depression, but only five showed a significant effect (OR 1.57-1.81, P ≤ 0.02). Treating VMS and depressive symptoms as continuous variables (n = 3) diminished the relationship. Three studies showed a significant association of depression leading to VMS (OR 1.62-1.94, P ≤ 0.01). We found little evidence for a specific effect of night sweats on the association between VMS and depressive symptoms. The effect might not be related to sleep disruption. CONCLUSIONS: There is a bidirectional association between VMS and depressive symptoms. The menopausal transition appears to increase the risk of recurrent episodes of depression that might not be explained only by VMS. Further investigation is needed to explain the differential effect of night sweats and hot flashes on depression.