PMDD and PMS: telling them apart and getting treatment

SASian Anderson, Writer and editor, MyGLP. Sources checked 5 November 2026.

PMS and PMDD are the same pattern at different strengths

Premenstrual syndrome, PMS, is the name for symptoms which arrive in the weeks before a period and ease once it starts. The Royal College of Obstetricians and Gynaecologists (RCOG) says 4 in 10 women have PMS symptoms, and 5 to 8% of them have severe PMS. Its Green-top Guideline No. 48 sets out how specialists diagnose and treat it.

Premenstrual dysphoric disorder, PMDD, is the severe end. The NHS PMS page describes symptoms like those of PMS but far more intense, with a greater effect on everyday life. They can include strong feelings of anxiety, anger or depression, and suicidal thoughts. The cause is unclear. The NHS says PMDD has been linked to a high sensitivity to normal hormone changes and to inherited genetic differences.

A 2024 systematic review and meta-analysis in the Journal of Affective Disorders pooled studies from around the world. It found 3.2% of women and girls met the criteria for a confirmed diagnosis of PMDD, and 7.7% met the criteria for a provisional diagnosis.

How the two compare

Track two cycles

The NHS advises a symptom diary for at least 2 menstrual cycles, brought to your GP appointment. Two cycles show your GP whether symptoms follow your period, and how hard they hit.

1. Mark day 1 of each period.
2. Each evening, score your main symptoms from 0 to 3: low mood, anxiety, irritability or anger, tiredness, sleep, bloating, breast pain, cravings.
3. Note any day you missed work, cancelled plans or argued with someone close.
4. Note any thought of self-harm, even a brief one, and tell your GP about it.
5. Add any new medicine, a dose change or a week of eating little, so you can see what lines up.

A free period app with a notes field works, as does a sheet of paper. What matters is filling it in daily, not from memory at the end of the month.

Treatments

The NHS lists self-help first, then treatment from your GP, then referral to a gynaecologist, psychiatrist or counsellor if symptoms persist.

SSRIs are the treatment with the strongest trial base. A Cochrane review concluded the evidence supports SSRIs for severe PMS. Taking them only in the second half of the cycle, the luteal phase, worked, as did taking them every day. Nausea, insomnia, headache and lower sex drive were the most common side effects, and women on an SSRI were about twice as likely to stop treatment because of side effects as women on placebo.

For severe PMDD a specialist may suggest a GnRH analogue. Chelsea and Westminster Hospital explains these create a reversible chemical menopause, so cycle-driven symptoms should stop. Hot flushes, low mood and vaginal dryness are common, so HRT is given alongside. Licensed use is limited to six months because of the risk to bone, and a bone density scan is done before starting and every 12 to 18 months. They can also confirm a diagnosis: if symptoms vanish when the cycle stops, the cycle is the cause.

The NHS mentions acupuncture, reflexology and supplements such as vitamin B6, calcium, vitamin D and magnesium, and says the evidence for them is limited. Check with a pharmacist before starting a supplement, in particular if you take other medicines.

PMDD and weight loss medicines

Three points are worth knowing if you take Mounjaro or Wegovy.

• Mood. In September 2024 the MHRA reviewed the evidence and found it does not establish a causal link between GLP-1 medicines and suicidal thoughts, self-harm or depression. The MHRA keeps monitoring. A diary still helps you and your prescriber see whether low mood follows your cycle, your dose days, or neither.
• The pill. If the combined pill is your PMS treatment, the MHRA warned in June 2025 that Mounjaro may reduce how well oral contraceptives work in people who are overweight. Ask whether a patch, ring or other non-oral option suits you.
• Nausea. Nausea is a common side effect of both SSRIs and the weight loss medicines, which the NHS tirzepatide page lists. Tell your GP and your prescriber about both medicines.

Cycle changes on a weight loss medicine can also move your PMS week around. Our guide to periods on weight loss injections explains why. In your 40s, PMS-like mood changes can be the perimenopause, which our menopause mood guide covers.

Being believed

PMDD has set diagnostic criteria and a treatment plan. A diary turns "I feel awful before my period" into two cycles of evidence. If your GP is unsure, ask for referral to a gynaecologist with an interest in PMS. You can also ask to see another GP at the same practice.

Sources

1. PMS (premenstrual syndrome) (NHS)
2. Management of premenstrual syndrome (Green-top Guideline No. 48) (Royal College of Obstetricians and Gynaecologists)
3. The prevalence of premenstrual dysphoric disorder: systematic review and meta-analysis (Journal of Affective Disorders, 2024)
4. Selective serotonin reuptake inhibitors for premenstrual syndrome (Cochrane Database of Systematic Reviews)
5. Gonadotropin releasing hormone agonists for PMS (Chelsea and Westminster Hospital NHS Foundation Trust)
6. MHRA finds evidence does not support a link between GLP-1 receptor agonists and suicidal thoughts, September 2024 (MHRA)
7. Weight loss injections: contraception warning for women, June 2025 (MHRA, via the Department of Health Northern Ireland)
8. Tirzepatide (NHS)