Symptom guide
PMDD vs PMS: how they differ and what to do
PMS is common and its symptoms usually ease once a period starts. PMDD (premenstrual dysphoric disorder) is a more severe, less common condition, recognised in UK clinical practice, where premenstrual mood symptoms are intense enough to seriously affect daily life, relationships or work. The key distinguishing pattern is timing: symptoms appear in the one to two weeks before a period and ease within a few days of it starting. This article cannot diagnose PMDD; that distinction needs a GP, usually helped by tracking symptoms across at least two full cycles. This is information, not medical advice.
What PMS is
The NHS describes premenstrual syndrome (PMS) as the physical and emotional symptoms many women experience in the days before a period, such as mood changes, irritability, bloating, breast tenderness and low energy. PMS is common, and for most women these symptoms resolve with or shortly after a period starts. Symptoms can range from mild to uncomfortable, but they do not typically stop someone from functioning in daily life.
What PMDD is
PMDD, premenstrual dysphoric disorder, is a more severe and less common condition, recognised in UK clinical practice, where premenstrual mood symptoms are intense enough to seriously affect daily life, relationships or work. It is a real, recognised condition, not simply a more intense version of ordinary premenstrual irritability, and it is taken seriously by GPs when the pattern fits.
The pattern that distinguishes them
The defining feature of PMDD is timing, not severity alone. Symptoms appear in the luteal phase, roughly the one to two weeks before a period, and ease within a few days of it starting. This cycle-linked pattern is what separates PMDD from a mood disorder such as depression or bipolar disorder, where symptoms tend to be constant through the month rather than rising and falling with the cycle.
This article cannot tell you which one you have, and it is not appropriate to self-diagnose PMDD, or to try to work out from an article alone whether your symptoms are PMDD, depression or bipolar disorder. If your mood symptoms are constant rather than clearly cycle-linked, or you are unsure which pattern fits, that distinction is something only a GP can properly assess.
PMS and PMDD side by side
| Feature | PMS | PMDD |
|---|---|---|
| How common | Common; most women experience some premenstrual symptoms | Less common |
| Symptom severity | Mild to uncomfortable; does not typically stop daily functioning | Intense enough to seriously affect daily life, relationships or work |
| Timing | Days before a period, cycle-linked | One to two weeks before a period (luteal phase), cycle-linked |
| Resolves | Eases with or shortly after a period starts | Eases within a few days of a period starting |
| Clinical status | Common experience, not a diagnosis | Recognised as a distinct condition in UK clinical practice |
Why tracking matters
The standard first step, consistent with NHS advice, is to track your symptoms across at least two full cycles, noting your mood, physical symptoms and their timing relative to your period. A simple diary or tracking app is enough. This gives your GP the information needed to assess whether your symptoms follow a cycle-linked pattern or a more constant one, which is far more useful than trying to describe it from memory at a single appointment.
What a GP might discuss
If PMDD is suspected, a GP might discuss a range of approaches depending on your situation and how symptoms affect you. These generally fall into lifestyle measures, talking therapies such as cognitive behavioural therapy, and in some cases medication, which can include certain antidepressants or hormonal treatment. None of these is a one-size-fits-all answer, and which approach, if any, is right for you is a decision to make with a GP, not something to select for yourself from this page.
Sources
- NHS: Pre-menstrual syndrome (nhs.uk/conditions/pre-menstrual-syndrome/)
- NHS: Urgent mental health support for a mental health crisis (nhs.uk/mental-health/advice-for-life-situations-and-events/urgent-mental-health-support-for-mental-health-crisis/)
Read more
- Period health: the full guide to cycles, heavy periods and PMS.
- Magnesium: what the evidence says about magnesium and women's health.
Frequently asked questions
What is the difference between PMDD and PMS?
PMS is common, and its physical and emotional symptoms, while sometimes uncomfortable, usually do not stop someone functioning day to day. PMDD (premenstrual dysphoric disorder) is less common and involves mood symptoms intense enough to seriously affect daily life, relationships or work. Both are linked to the menstrual cycle, but PMDD is more severe and is recognised as a distinct condition in UK clinical practice.
How do I know if I have PMDD or something else?
This article cannot tell you which one you have, and self-diagnosis from an article is not appropriate. The key clue clinicians look for is timing: PMDD symptoms are cycle-linked, appearing in the one to two weeks before a period and easing within a few days of it starting. If mood symptoms are constant through the month rather than tied to your cycle, or you are unsure, that distinction needs a GP, usually helped by tracking symptoms across at least two full cycles.
How is PMDD diagnosed?
A GP assesses PMDD by looking at the pattern of your symptoms over time, which is why symptom tracking across at least two full cycles, noting mood, physical symptoms and timing relative to your period, is the standard first step. This gives a clearer picture than trying to recall symptoms from memory and helps distinguish a cycle-linked pattern from a mood disorder that is constant through the month.
What helps with PMDD?
A GP might discuss a number of approaches depending on your situation, including lifestyle measures, cognitive behavioural therapy, and in some cases medication such as certain antidepressants or hormonal treatment. Which of these is right, if any, is a decision to make with a GP rather than something to self-select from an article.
This is information, not medical advice, and is not a substitute for a registered clinician. It cannot diagnose PMDD or any other condition. If you are concerned about your mood or your cycle, speak to your GP. Return to the period health hub.
Editor, Her Vitals
Oliver leads Her Vitals's editorial coverage of women's life-stage health and supplements. He curates and reviews existing branded products across trying to conceive, pregnancy, postnatal, perimenopause, menopause and the senior years, weighing what the evidence supports against guidance from bodies such as EFSA, the NHS and NICE, and is clear that the content is information rather than medical advice.
Last reviewed: 4 August 2026
Reviewed by Oliver Mackman, Editor. Editorial review against published guidance; not a clinical review.