PMS vs PMDD: What’s the difference
PMS and PMDD are both premenstrual disorders, but they differ in severity and classification. PMS is more common, affecting approximately 20-40% of menstruating women, including adolescents. PMDD is less common, impacting approximately 1.2-6.4% of women, and is characterized by more severe symptoms. Unlike PMS, PMDD is formally classified as a mental health condition.
What Is PMS?
PMS (Premenstrual Syndrome) is characterized by symptoms that occur during the premenstrual (luteal) phase of the menstrual cycle. Symptoms are usually most significant the week before bleeding begins. PMS symptoms occur during ovulatory cycles (meaning you cannot experience PMS while on an oral contraceptive pill). There are hundreds of symptoms that can be part of the PMS experience, but common areas of impact include concentration, energy, efficiency, interest in work, and mood.
What Is PMDD?
For a PMDD diagnosis, at least 5 symptoms must be present in the week before your period, improving within a few days after the onset of bleeding and becoming minimal or absent in the week after. At least one of the following core symptoms must be present: mood swings/labile affect, irritability or anger, depressed mood or hopelessness, and/or anxiety. Additional symptoms can include decreased interest in usual activities, difficulty concentrating, fatigue, changes in appetite, sleep disturbances, feeling overwhelmed, or physical symptoms like joint pain, breast tenderness, or bloating.
What Causes PMDD?
The underlying cause of PMDD is believed to be a sensitivity to hormonal fluctuations during the luteal phase of the menstrual cycle. Those with PMDD have estrogen and progesterone levels similar to those without it. What differs is how the brain responds to the rise and fall of these hormones, which then disrupts serotonin and GABA signaling.
PMS vs PMDD: Side by Side
Both PMS and PMDD are characterized by mood symptoms that occur during the 1-2 weeks before your period, and resolve shortly after the period begins. The main difference is the severity of the symptoms and the functional impact. If you feel so poor during the luteal phase that is hard to do your usual activities, attend work or school, or your relationships are negatively impacted, it is worth discussing this with your primary care provider.
What Else Can Look Like PMS or PMDD?
It is important to have a thorough assessment done to rule out other causes of these symptoms. Underlying mood disorders like anxiety or depression can worsen during the luteal phase, but if they are also present month long, this is a different condition that needs different support. Other medical problems like iron deficiency, anemia, thyroid disorders, and perimenopause can also masquerade as PMS or PMDD.
How Is PMDD Diagnosed? (Why Tracking Matters)
PMDD is diagnosed based on symptom experience, not blood tests or imaging. To meet the diagnostic criteria, you must track your symptoms daily over at least two menstrual cycles, using a validated tool like The Daily Record of Severity of Problems. If there is a pattern of mood symptoms that recur in the premenstrual phase, and resolve around the onset of menstruation, you may qualify for the diagnosis. Importantly, symptoms must have occured in most cycles over the past year, cause clinically significant distress or impairment in social or occupational function, and there must be a symptom free interval in the follicular phase (usually ~cycle day 1-14).
What are the conventional approaches to PMS and PMDD?
The mainstays of PMS & PMDD treatment are:
Selective Serotonin Reuptake Inhibitors (SSRIs) - considered a first line treatment for PMS and PMDD. These can be taken continuously or dosed only in the luteal phase. These alter brain neurotransmitter function and are reliably effective for mood symptom. However they may cause side effects like emporary stomach upset, nausea, or shifts in libido.
Oral contraceptive pills (OCPs) - supress ovulation, which eliminates the wild fluctuation in hormone levels that trigger symptoms. The pill can be taken continuously (skipping the placebo week) to further limit symptoms. It’s worth knowing that occaisionally taking an OCP can worsen symptoms
Cognitive behavioural therapy (CBT) - is a psychotherapy practice with a mental health professional that focuses on addressing unhelpful thinking and building coping skills. It is effective for PMS and PMDD.
When to Get Urgent Help:
PMDD isn’t just feeling irritable before your period. It’s strongly associated with suicidality, and those thoughts can come and go with your cycle. If you are thinking about suicide or hurting yourself, or feel unsafe, in Canada, call or text 9-8-8 any time, day or night. If you’re in immediate danger, call 911 or go to your nearest emergency department. If you can, tell someone you trust how you’re feeling and where you are.
Frequently Asked Questions
Is PMS caused by low progesterone?
PMS is not caused by any one hormone being too high or low. PMS is triggered by the change in hormone levels before your period, and some people’s brains are more sensitive to this change.
What bloodwork should I get done if I have PMS or PMDD?
Bloodwork to investigate your health wholistically is often not a bad idea, but there is no test for PMS, nor is hormone testing recommended if you’re experiencing cyclic mood symptoms. Discuss testing other factors that can look like PMS (i.e. iron deficiency, thyroid dysfunction) with your health care provider, to exclude those as possible contributors to your symptoms.
If I have PMS and signs of high estrogen, what should I do?
You may have been told you have “estrogen dominance” and this is at the route of your PMS. “Estrogen dominance” is everywhere online, but it isn’t a medical diagnosis. For PMS/PMDD, the “too much estrogen” idea doesn’t hold up. People with PMDD generally have normal estrogen and progesterone levels. What differs seems to be how sensitive they are to normal hormone shifts.
What are some natural approaches to managing PMS or PMDD?
Exercise can boost mood and promote natural endorphin release.
Psychotherapy and Cognitive Behavioral Therapy (CBT)
Mindfulness training, including guided meditation and breathing exercises
Acupuncture and acupressure, which may improve both physical and psychological symptoms of PMS
Targetted nutritional supplements: Omega 3s, Calcium and Vitex (also called Chaste Tree) have the most evidence.
Want Support With PMS or PMDD?
If your symptoms are getting in the way of your training, your work, or just your week, you don’t have to figure it out on your own. In a visit, we go through your symptoms, your cycle, your training, your nutrition, your bloodwork, and your preferences for care. Book a visit with me when you’re ready to start feeling good for more than just half of your cycle.
References:
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About the author: Dr. Katrina Allison, ND is a naturopathic doctor in North Vancouver and Kitsilano who works with active women and female athletes on hormonal health, nutrition, and performance. She's also a competitive marathoner.
This post is for education only and isn't a substitute for individualized medical advice.