Perimenopause-related mood disorders cause significant distress to a potentially large number of women. The demand for effective therapeutic alternatives to estrogen for treating these mood disorders is considerable, as is the need to define clinical or biologic markers that may predict successful response of mood disturbances to phytoestrogens or selective estrogen receptor modulators (SERMs). Further, the study of potential biological mechanisms underlying both perimenopause-related mood disorders and their response to treatment may offer the possibility of uncovering some etiopathogenic mechanisms involved in these and related mood disorders.