PMDD vs. PMS: Key differences explained by a doctor

We often use the term premenstrual syndrome (PMS) as a catch-all name for any symptoms you feel around your period. But did you know that it is actually a medical diagnosis? As many as 90% of women experience noticeable symptoms before their periods. However, it’s estimated that 20% to 30% of women experience PMS. Here’s the difference between the two: PMS means having symptoms that occur at least three cycles in a row and are severe enough to interfere with your day to day life. If you recognize this, then you’re not alone.

In rarer cases, PMS symptoms, especially PMS mood symptoms, are much more severe, enough to seriously impact a person’s day-to-day life. This is known as premenstrual dysphoric disorder (PMDD).

While the symptoms of PMS are often compared to PMDD, they aren’t the same. Here, a doctor outlines the key differences between the two conditions, including symptoms, treatment, and why it’s important to speak to your doctor to get a proper diagnosis.

Disclaimer: In this piece, we are going to touch on symptoms of PMDD such as depression, anxiety, and self-harm. If you find any of these topics difficult to discuss, feel personally affected, or would like more support, you can find helplines in your country here. 

Key takeaways about PMDD vs. PMS

• You might start to feel the symptoms linked to PMS or PMDD one to two weeks before your period, in the second half of your menstrual cycle. They’re linked to fluctuations in your hormones during this time. 
• While the signs are similar, PMDD symptoms are far more severe than those of PMS and tend to center more around a person’s mood or emotions.
• PMS is more common. Most people experience at least one PMS symptom in their reproductive years. PMDD affects a much smaller number of people. Understanding the differences between the two can help you cope with how you’re feeling. 
• If you have any concerns about the symptoms you experience around your period, then speak to your doctor. This absolutely isn’t something that you need to manage alone, and there are effective treatment methods out there. 

What is PMS? 

The term PMS is often used to describe any changes in the way you feel before your period. However, it is in fact a diagnosis that describes a specific set of symptoms.

Many of us will experience some symptoms before our period. Research has shown that up to 90% of women of reproductive age report at least one change in the way they feel before their period. However, only 20% to 30% of women experience PMS. Symptoms are recognized as PMS if they occur during at least three cycles in a row and are severe enough to interfere with normal life. 

PMS symptoms are generally experienced one to two weeks before getting your period. This is during the second half of the menstrual cycle, after ovulation, and is known as the luteal phase. 

While the exact cause of PMS isn’t known, it’s been linked to changing hormone levels during the menstrual cycle. Symptoms of PMS usually subside within four days of getting your period, but all of us are different. We won’t all experience PMS in the same way, and you may not notice it every cycle. 

What are the symptoms of PMS? 

The symptoms of PMS vary from person to person. Once you know what’s typical for you, you may use it as a sign that your period is coming. It’s important to remember that everyone is different, and your symptoms may even vary from month to month. 

Dr. Jenna Beckham, an obstetrician, gynecologist, and complex family planning specialist at WakeMed Health and Hospitals and Planned Parenthood South Atlantic, North Carolina, US, who sits on Flo’s expert board, explains: “PMS symptoms can be mood or emotional, like anger, sadness, outbursts, or physical, like breast pain, headaches, or bloating.”

Emotional symptoms of PMS include:

• Mood swings
• Feeling irritable
• Having outbursts 
• Crying more than usual
• Anxiety
• Sleeping problems
• Depression
• Difficulty concentrating 
• Lower sex drive
• Feeling tired (Read more about causes of fatigue in the run-up to your period.)

Physical symptoms of PMS include: 

• Oily skin or acne breakouts
• Sore breasts 
• Backaches
• Food cravings
• Painful joints
• Headaches
• Bloating
• Constipation or diarrhea
• Abdominal pain or cramps (Read more about the reasons for painful cramps before your period.)
• Feeling nauseous (Read more about period nausea.) 

This isn’t an exhaustive list. There are a huge number of PMS symptoms. And as we said, it can look really different each cycle. “There are more than 150 physical, behavioral, and emotional symptoms that have been ascribed to PMS in literature,” says Dr. Beckham. “Most often, the types of symptoms individuals experience are consistent across cycles and last for an average of six days per month.” 

There are some things you can do at home to help alleviate your PMS. For example, you can try to eat healthily, move your body in a way that feels good to you, and try to get plenty of sleep. You can also speak to your doctor about the emotional and physical symptoms around the time of your period. They will be able to walk you through why you might be feeling that way and the best next step. 

What is PMDD?

So, we’ve discussed PMS, but what about premenstrual dysphoric disorder (PMDD)? PMDD is a more severe form of PMS. Although the symptoms of PMDD are similar to those of PMS, if you have PMDD, you are likely to experience more intense symptoms linked to mood changes. These symptoms also have a greater negative impact on your everyday life. It’s important to note that PMDD is far less common than PMS. It’s thought that about 2% to 5% of women and girls globally have PMDD. 

Like PMS, PMDD happens in the second half of the menstrual cycle, after ovulation and during the luteal phase. Like PMS, symptoms of PMDD usually go away within four days of your period starting. It’s also not known what causes PMDD. It’s been linked to both changing hormone levels during the menstrual cycle and genetics.

“PMDD is the most severe form of PMS,” explains Dr. Beckham. “This diagnosis requires that the symptoms are associated with significant distress or interference with daily activities — like school, work, social life — and have been present in most menstrual cycles that have occurred in the previous year.”

What are the symptoms of PMDD? 

The symptoms of PMDD are similar to those of PMS, but they are notably more severe and can majorly affect your everyday life. Symptoms can be physical, emotional, and cognitive. They can vary from person to person.  

Dr. Beckham highlights the American Psychiatric Association, which states that at least five of the below premenstrual symptoms are required to meet the diagnoses of PMDD:

• Severe emotional changes, like mood swings or sudden sadness
• Noticeable anger or irritability 
• Sense of hopelessness, depressed mood, or self-critical thoughts 
• Tension, anxiety, or feeling on edge 
• Difficulty concentrating 
• Easy fatigability or decreased energy
• Change in appetite, food cravings, or overeating 
• Diminished interest in usual activities 
• Feeling overwhelmed or out of control 
• Physical symptoms like breast tenderness, blоаting, weight gain, or joint and muscle aches 
• Sleeping too much (hypersomnia) or not sleeping enough (insomnia)

Some of the symptoms of PMDD can lead people to think about harming themselves or have suicidal thoughts. This can feel really scary and is a lonely place to be. If that’s you, seek help from your doctor immediately. And remember, you are not alone. There are lots of effective treatments for these symptoms. Your doctor will be able to help you find the right fit for you. You can also use one of these helplines. 

Key differences between PMS and PMDD

The key difference between PMS and PMDD is the severity and number of symptoms. While PMS symptoms can certainly vary — from mild to more severe — PMDD has a serious, negative impact on your daily life. As Dr. Beckham puts it, “The key differences are the number of symptoms, severity, and duration.”

Below are more key differences between PMS and PMDD:

• PMS affects around 20% to 30% of women, whereas PMDD is much rarer. PMDD affects between 2% to 5% of women and girls globally. 
• The symptoms of PMDD are far more severe than PMS and have a bigger negative impact.
• The symptoms of PMDD may last longer than those of PMS.
• The diagnostic process for PMDD is generally more rigorous than that for PMS, requiring five or more symptoms to be present.

While there are key differences between PMS and PMDD, your doctor may use similar methods to diagnose you. They may carry out a physical exam, ask for your medical history, or get you to keep a diary of symptoms for several months to monitor your symptoms and the impact of any treatment provided. You can track some of your symptoms using the Flo app. This may help you spot patterns and understand what’s typical for you. 

When to seek medical help

While many of us accept that we will feel different before our period starts, you don’t have to manage PMS symptoms alone. You may choose to make some lifestyle changes such as getting some fresh air and moving your body if you can. This may also be a good time to give yourself some space to do the things you find calming. 

If your symptoms are impacting your daily life, then it’s really important that you speak to your doctor immediately. 

Some treatments that may be recommended for both PMS and PMDD include:

• Antidepressants, like selective serotonin reuptake inhibitors (SSRIs)
• Hormonal medicine, like birth control
• Cognitive behavioral therapy

It’s also important to see your doctor for a proper diagnosis, as the symptoms of both PMS and PMDD can be confused with other conditions, like thyroid disorders, depression, or anxiety. 

By using the Flo period-tracking app, you can monitor your symptoms during your menstrual cycle. So if your doctor asks you for a log of your symptoms, you’ll already have it, meaning they can provide a quicker and more accurate diagnosis, alongside a personalized treatment plan. 

As Dr. Beckham concludes, “It can be helpful to track your cycles as well as the symptoms you are experiencing, including when they occur in relation to your cycles. You should of course also talk to your provider, who will ask you to track this information if you have not done so already.”