SSRIs for PMDD: how they work, and what to expect

PMDD isn't caused by abnormal hormone levels. In people with PMDD, estrogen and progesterone are usually in the normal range. The difference is how the brain responds to the normal rise and fall of estrogen and progesterone after ovulation.

Serotonin sits in the middle of that response. Progesterone's breakdown product, allopregnanolone, acts on the same calming brain receptors that serotonin helps regulate. When that system is extra sensitive, the drop before your period lands as rage, tears or dread. SSRIs keep more serotonin available, which steadies the system through the shift.

In depression, SSRIs take four to six weeks. In PMDD they often work within the first one or two days of a cycle. That speed is what makes luteal-phase dosing possible: you take the medicine from around ovulation until your period starts, then stop.

There are three common ways to take them:

• Every day, all month. Best studied, and simplest if your cycle is irregular.
• Luteal phase only, from about day 14 to the start of your period.
• Symptom-onset, starting the day symptoms begin. Less studied, and works for some people.

In the US, fluoxetine, sertraline and paroxetine CR are approved for PMDD. Escitalopram and citalopram have good trial data too. No single SSRI clearly beats the others, so the choice usually comes down to side effects and what you have tried before. Doses are often lower than for depression.

If one SSRI does not help after two or three cycles, another often does. Venlafaxine, an SNRI, is a common next step.

The most common are nausea, tiredness, trouble sleeping, sweating and lower sex drive. They are usually mild and often fade within a couple of weeks. Luteal-phase dosing can mean fewer side effects overall, because you take the medicine for half the month.

Stopping suddenly after daily use can cause dizziness and irritability for a few days, so talk to your doctor before you stop.

No. Medicine turns the volume down. It does not tell you what to say when your partner walks out mid-sentence, or how to answer a two-line email from your manager. Cognitive behavioural therapy has its own evidence in PMDD, and people often do best with both.

That is the gap Niyora was built for. When the hard moment still comes, Moon helps you see it from another angle, settle your body, and choose your next words.