The complete guide to PMS and PMDD
What to expect from this article: Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD) are hormonally driven conditions that affect mood, energy, and physical health in the lead-up to menstruation. PMS is common and usually manageable, while PMDD is less common but more severe and disruptive. This article delves into the differences, underlying causes, diagnosis methods and available support, along with the history of hormonal health and evolving research.
Why this article matters.
PMS and PMDD affect millions of women* and others assigned female at birth. Yet they remain under-recognised and often misunderstood. While PMS is familiar to many, PMDD can go undiagnosed for years, with symptoms often misattributed to anxiety or depression.
At Evelyn, we believe clarity is key. This article breaks down the science and lived experience behind PMS and PMDD to help you better understand your body and find the support you deserve.
What is PMS?
PMS refers to a group of emotional and physical symptoms that appear after ovulation and before your period. These can include irritability, low mood, bloating, fatigue, and breast tenderness. For most people, symptoms are mild and manageable and pass when menstruation begins.
The exact causes aren’t fully known, but research suggests links to serotonin levels, inflammation, and heightened sensitivity to hormonal changes.
Read our full article: What is PMS?
What is PMDD?
PMDD is a hormone-related mood disorder that differs from PMS by presenting intense and often debilitating emotional symptoms. Individuals may feel anger, hopelessness, anxiety, or even suicidal thoughts in the week or two before their period. These feelings usually lift once bleeding begins.
PMDD affects up to 8% of women* and people assigned female at birth (AFAB) during their reproductive years, and is officially classified as a depressive disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Many describe it as feeling like ‘a different person’ for a week or two every month.
Explore our PMDD explainer: What is PMDD?
PMS vs PMDD: Understanding the difference
Both PMS and PMDD occur in the luteal phase, but while PMS might cause emotional sensitivity or discomfort, PMDD can deeply affect your daily functioning and relationships. If your symptoms leave you feeling out of control or consistently unwell, it may be more than just PMS.
What causes PMS and PMDD?
Hormonal fluctuations are the primary trigger for both PMS and PMDD, but why do some people react so strongly to normal hormonal changes? That’s the question researchers are still trying to answer.
Current theories suggest an interplay between genetics, neurotransmitter (especially serotonin) sensitivity, immune system activation, stress, trauma history, and even gut health. The causes are likely multi-layered, which is why solutions must be too.
Deep dive: What causes PMS & PMDD?
A historical blind spot.
The lack of awareness around PMS and PMDD isn't accidental. Women's health, particularly anything related to menstruation, has historically been under-researched and underfunded. For centuries, symptoms were dismissed as 'hysteria' or emotional instability. Even today, many healthcare providers receive little formal training on PMDD.
This gap in medical knowledge is slowly closing, but not fast enough. Understanding the historical context helps us advocate for better care.
More on this: History of women’s health
Spotting the signs.
The emotional toll of PMDD can be difficult to explain. Many experience rage, despair, or panic attacks so intense they feel destabilising. Others describe complete personality shifts each month. PMS, in contrast, is more likely to cause manageable mood swings, bloating, and fatigue.
If your symptoms are cyclical and severe, it’s worth exploring a formal diagnosis.
Why PMDD is so often misdiagnosed.
PMDD can mimic other mental health conditions. It's often mislabelled as anxiety or depression, especially when clinicians aren't trained to link symptoms to the menstrual cycle. Without cycle tracking, the hormonal rhythm is easy to miss.
This misdiagnosis can delay access to targeted support and leave people feeling misunderstood.
Read more: How PMDD is misdiagnosed
How to track your cycle for clarity.
The most effective way to identify PMDD is by tracking your symptoms across at least two full cycles. Tools such as the Daily Record of Severity of Problems (DRSP) or cycle tracking apps can reveal patterns that align with your menstrual phases.
This data not only helps you understand your experience but also provides crucial information for your GP or specialist.
How-to guide: Cycle tracking for diagnosis
The different types of PMDD.
PMDD can vary greatly from person to person. Some experience a ‘pure’ presentation, meaning symptoms only occur during the luteal phase, while others have coexisting mood disorders, such as anxiety or depression, which intensify cyclically. In addition, there are timing variations, with symptoms starting earlier or later in the cycle.
Recognising your subtype can help tailor your treatment plan.
Getting the right support.
There is no single cure for PMS or PMDD, but there are effective management options. These include lifestyle changes (e.g. nutrition, exercise, stress reduction), talking therapies like cognitive behavioural therapy (CBT), selective serotonin reuptake inhibitors (SSRIs), also known as antidepressants, and, in some cases, hormonal treatments. Many people also find relief with evidence-backed supplements.
Evelyn’s Super Regular® is formulated to support mood and hormone balance using nutrients shown to regulate neurotransmitter activity and inflammation.
Find out more about Super Regular®
You're not alone.
Cyclical symptoms can feel isolating, especially if they’ve been misunderstood or dismissed. At Evelyn, we speak to people every day who struggle with symptoms for years before joining the dots and recognising that it’s PMDD.
With the right knowledge and tools, relief is possible. Support starts with self-awareness and continues with the right care.
What next?
- Talk to your GP about PMDD and tracking your cycle
- Explore our articles and clinically formulated support
- Try Super Regular®
In this article:
- We defined PMS and PMDD
- We explored causes, symptoms, and how they differ
- We discussed misdiagnosis and the importance of cycle tracking
- We looked at treatment pathways and emotional impact
Related reading:
References:
- NHS: Premenstrual syndrome
- IAPMD: PMDD Research
- NCBI: PMDD Diagnostic Overview
Disclaimer: This content is for informational purposes only and is not intended as medical advice. Always speak to a qualified healthcare professional about any health concerns.
*At Evelyn, we often use the word ‘women’ in our articles as a shorthand to describe the people in our community and others who experience PMS and PMDD symptoms. We acknowledge that not everyone affected by these conditions identifies as a woman, and we want to be clear: Evelyn is for anyone navigating the hormonal challenges associated with PMS and PMDD, regardless of gender identity.
We welcome people of all identities and expressions to our community. We are committed to fighting for access to better hormonal health education, support, and treatment for everyone who needs it.
In our educational content, we aim to be both inclusive and medically accurate. Most scientific studies relevant to PMS and PMDD have been conducted with cisgender female cohorts. As a result, using the term ‘women’ often best reflects the language used in the available research. When we refer to ‘women’, it is in this context – not as an exclusive definition of who can be affected.
Within our community, we strive to reflect the diverse voices of those living with PMS and PMDD – including trans men, non-binary and gender non-conforming people – and we will continue to evolve our language as the conversation around hormonal health expands.