'Bachelorette' contestant Kaitlyn Bristowe says she experiences 'hormonal depression' during her period. The condition can trigger mood swings and anxiety.

• Kaitlyn Bristowe, former 'Bachelorette' contestant, said she has hormonal depression during her period.
• For many people with periods, their cycle can cause mental health conditions, like PMS and PMDD.

Kaitlyn Bristowe, former "Bachelorette" contestant, shared her struggles with period-related "hormonal depression" in an Instagram post on Monday.

Bristowe said her periods usually bring bouts of anxiety, depression, and emotional instability that used to leave her feeling "bat shit CRAZY."

"I never put two and two together that it was always around the same time," Bristowe wrote. "Hormones are the devil and they are stronger than me. I just wanna crawl into my own bed and cry today. But I have no time."

"It puts my relationship through hard times, it puts me in shameful spirals, and I just sat on a 5 hour flight talking myself out of a panic attack," she continued.

Bristowe is not alone. According to the Harvard School of Medicine, at least 20% of people who get periods deal with some form of menstrual-related mood disorder.

These disorders include premenstrual syndrome (PMS) and premenstrual dysphoria disorder (PMDD).

While people with PMS describe symptoms like cramps, tender breasts, and slight changes to their mood, at least 5% to 8% of people who menstruate have more severe PMDD symptoms, like debilitating mood changes that come with the physical pain of their cycle.

People who struggle with PMDD often feel intense lows and periods of anxiety before and during their period

The hormonal changes that occur throughout a person's menstrual cycle can lead to a serotonin deficiency, which can cause intense mood swings and debilitating anxiety and depression closer to a person's period.

PMDD symptoms typically start two weeks before someone has their period, according to Harvard Health Publishing.

Similar to the spirals Bristowe described, Johns Hopkins Medicine states these symptoms include agitation, insomnia, aggression, anxiety, and depression.

According to Dr. Andrea Chisholm, an OB/GYN at the Cambridge Health Alliance, PMDD is often misdiagnosed or written off as a minor concern by medical professionals, which can exacerbate the condition in the long-term.

"Sometimes they go undiagnosed, being told they are just hormonal and need to get over it. And sometimes they are overdiagnosed," Chisholm wrote. "Unfortunately, it is all too common for women with PMDD to be incorrectly diagnosed with bipolar disorder."

People with PMDD should seek treatment and not ignore their symptoms. Treatments for PMDD range from changing your diet to hormone therapies to anti-depressants, as there is not one-size-fits-all approach to managing it.