PMDD - premenstrual dysphoric disorder - is a mental health disorder which causes severe psychological and sometimes physical symptoms. It can affect women at any point in their lives but often coincides with moments of significant hormonal changes - including puberty, having a baby, or going through the menopause. Tap the link in @BBCNews's bio to read more about a tool, devised by researchers in Scotland, to help those with suicidal thoughts brought on by the disorder. #PMDD #BBCNews