PMDD and endometriosis are two separate conditions.
Endometriosis is a condition in which the tissues of the endometrium (the inner lining of the uterus) are present in other organs inside your body. In many patients, this can cause significant pain, especially during periods.
Symptoms of endometriosis can include:
Pain. This is the most common symptom and can include: dysmenorrhea (painful menstrual cramps), chronic pelvic pain (long-term pain in the lower back, abdomen, and pelvis), dyspareunia (pain during sex - especially pain with deep penetration), pain with defecation or urination. Infertility, or not being able to get pregnant.
Stomach (digestive) problems. These include diarrhea, constipation, bloating, or nausea, especially during menstrual periods.
Read more on endometriosis here.
PMDD is a disorder of the brain, especially how the brain responds to changes in menstrual hormones. This means that those with PMDD have an abnormal negative reaction to the natural rise and fall of estrogen and progesterone that happens with each menstrual cycle.. Whilst it has some physical symptoms such as bloating, fatigue, joint pains etc it does not cause heavy bleeding. The symptoms are mainly psychological.
Endometriosis is a primarily a gynecological issue, though the pain and impairment caused by endometriosis may worsen other psychiatric conditions. You can read more about PMDD here: www.iapmd.org/about-pmdd
There is currently no evidence of a biological relationship between endometriosis and PMDD. Patients with endometriosis are not at increased risk of having PMDD, and patients with PMDD are not at increased risk of having endometriosis.