Mood swings during menopause are caused largely by the hormonal transitions women go through during this time. Hormones, such as estrogen, influence the production of serotonin, which is a mood-regulating neurotransmitter.
However, there are other causes of mood swings. Other menopause symptoms - such as hot flashes, night sweats, physical changes, and fatigue - can cause or intensify mood swings, but these symptoms are generally caused by hormonal imbalance as well.