PMS and Depression: What's the Connection?

Many women will recognize this: Just before your period, it sometimes feels like a dark cloud hangs over you. You feel more easily affected, have less energy, or see things more negatively than usual.

These mood swings are part of your natural cycle, but for some women, they're so intense that they impact their daily lives. This is called premenstrual syndrome (PMS).

In the Netherlands, it's estimated that about one in five women experiences PMS symptoms. These symptoms are not only linked to hormonal fluctuations, but there are also indications that changes in the serotonin system play a role.

And when serotonin (the "happiness chemical") drops, it can affect your mood. Sometimes so strongly that it mimics depressive symptoms. But why does this affect some people more than others?

In this article, I'll answer that question. And I'll tell you what science has discovered about the link between PMS, serotonin, and depression.

PMS stands for premenstrual syndrome . This is a combination of physical and emotional symptoms that occur in the days to two weeks before menstruation .

Once menstruation starts, the symptoms usually disappear again.

Common symptoms include:

• Irritability or becoming angry quickly
• Mood swings
• Tender or painful breasts
• A bloated feeling
• Headache or stomach ache
• Fatigue or insomnia
• Sadness or crying spells for no apparent reason

PMS can noticeably affect daily life. But for a smaller group, the impact is particularly severe.

Then we speak of PMDD (Premenstrual Dysphoric Disorder) , a severe form of PMS in which mood complaints are in the foreground.

Your mood just before your period doesn't change just like that.

In the second half of your cycle , known as the luteal phase , a lot happens in your body and brain. Your hormones fluctuate, and these changes directly affect the substances that determine how you feel.

Let's take a step-by-step look at what exactly happens:

After ovulation, progesterone rises. Estrogen drops briefly, peaks again mid-luteal phase, and then drops again. If fertilization doesn't occur, both hormones only drop in the days just before your period.

These fluctuations occur in all women and can affect all kinds of physical processes, such as your energy levels and fluid balance.

What mainly plays a role in PMS is that some brains react more sensitively to these normal hormonal changes.

Estrogen and progesterone interact with your brain through the neurotransmitters that influence your mood, sleep, and focus.

• Estrogen can support the activity of the serotonin system.
• Progesterone (and especially its breakdown product allopregnanolone) works through the GABA system, which helps us relax.

Due to the changed hormonal balance, the functioning of these systems can temporarily shift, making signal transmission between brain cells less smooth.

The result? You may feel emotional, overstimulated more quickly, or depressed more than normal. (2)

Not everyone reacts to hormonal fluctuations in the same way. Some women are naturally more sensitive to changes in their brains, and that's precisely the core of PMS.

How you respond to these fluctuations is partly determined by genetics , but is also influenced by stress , nutrition , sleep and exercise .

There is considerable scientific interest in this topic. Several studies have shown that the serotonin system appears to function differently in women with PMS or PMDD. (3)(4)

One possible explanation is that their brains absorb more serotonin in the second half of the cycle, meaning less is available temporarily. This is shown by brain scan (PET) studies. (5)

For women who are sensitive to this, small things can have a big effect more quickly.

Stimuli like stress or a lack of sleep can affect the functioning of the serotonin system, contributing to a dip in mood or increased irritability. Lifestyle factors like exercise and daylight also play a role.

PMS clearly affects how you feel. But does that also mean it can lead to depression?

Research shows that there is indeed a link between PMS (and the more severe form PMDD) and depressive symptoms.

A recent meta-analysis of 39 studies found that among women with PMDD or severe PMS, approximately 42–49% also have a mood disorder, such as depression.

This indicates a clear overlap: Women who are more sensitive to hormonal fluctuations also appear to be more susceptible to mood swings or depression. (6)

What many people don't know is that approximately 90% of the serotonin in your body is produced in the intestines , not in the brain itself. This gut serotonin primarily influences your digestion and bowel movements, but it doesn't reach the brain directly.

Yet, your intestines and brain are in constant contact via the gut-brain axis . Nerve pathways, immune signals, and substances produced by gut bacteria play a role in this process.

Factors like stress, sleep, and diet can influence this communication. When your gut flora becomes unbalanced, for example, due to stress, a lack of fiber, or a limited diet, this can alter the signal transmission along the gut-brain axis.

Some studies suggest that this may be indirectly related to mood changes or increased sensitivity to stimuli around menstruation.

That's why scientists are increasingly looking at the role of gut health, nutrition, and probiotics in women with PMS or PMDD. Not because nutrition directly increases serotonin, but because a healthy gut contributes to balanced communication between the body and the brain. (7)(8)(9)