What is the difference?
Premenstrual syndrome vs PMDD
PMS and PMDD both describe symptoms in the days before a period that ease once it starts, so PMDD is sometimes dismissed as "just bad PMS". The difference is severity: PMDD is a recognised condition in which mood symptoms seriously disrupt life.
General information, not medical advice. For advice about your own situation, talk to a clinician, pharmacist or sexual health clinic.
Premenstrual syndrome
Premenstrual syndrome (PMS) is a set of physical and emotional symptoms, such as bloating, breast tenderness, irritability or low mood, that appear in the days before a period and ease once it starts.
Full entryPMDD
Premenstrual dysphoric disorder (PMDD) is a severe form of premenstrual distress in which depression, anxiety, anger or mood swings in the days before a period significantly disrupt life.
Full entrySide by side
In short
PMS is common premenstrual discomfort; PMDD is a severe, recognised condition that deserves medical attention, and anyone whose mood becomes dangerous should seek urgent help.
What they have in common
Both follow the menstrual cycle, appear before a period and lift after it starts, and a symptom diary helps with both.
Sources
More comparisons
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Last reviewed 10 October 2026. Spotted a mistake?