"Life is so beautiful," one woman says, tears streaming down her face.

"It's my relationship with myself that was scaring me," a man says, after breaking down in heavy sobs.

"I thought I didn't like me," another woman says, before pointing to her chest. "This, whatever it is, in here − it's always been here."

These are the emotional words of people fresh off a darkness retreat, in which they spent days in a cabin in total darkness, with nothing to occupy them but their own thoughts.

Darkness retreats have sparked buzz on social media, with Sky Cave Retreats, which offers this experience in southern Oregon, sharing videos on Instagram of people taking off their blindfolds and looking at the outside world for the first time after the retreat, sometimes to the tune of hundreds of thousands of likes and comments. The intense experience has also been touted by celebrities, like Aaron Rodgers, who did one in February, and Aubrey Marcus, the CEO of the lifestyle brand Onnit, who discussed darkness retreat in a viral video this year.

Despite these emotional videos, however, mental health experts say the ramifications of darkness retreats on the psyche haven't been thoroughly studied, and even Sky Cave Retreats' founder Scott Berman warns the experience is much more difficult than how social media makes it out to be.

"For everyone, it's really challenging," he says. "Being in the dark, stepping out of time and being completely alone is a lot harder than anyone imagines."

What happens in a dark retreat?

Darkness retreats are offered at various locations around the world and have differing protocols. Some plan activities for participants in the dark, while others leave them alone to meditate, sleep or do whatever they please.

Sky Cave Retreats follows the latter model and typically lasts three to five days, at the cost of $265 per night, including meals. Berman says about half of those who seek out his darkness retreat have a spiritual background.

Sometimes, he says, spiritual seekers come to the retreat with expectations of what it will do for them. This, he says, is the opposite of what the retreat should be, which is to abandon expectations and experience who you are when separated from outside pressure and opinions.

Josh Biddle, a palliative care physician, sought out a darkness retreat after coming across videos of people sharing their revelations from the experience on social media.

The four nights he spent in darkness in November, he says, were fruitful, but extremely taxing, much more so than the typical meditation retreats he'd done in the past.

"The hardest thing is really just the unrelenting nature of it," he says. "Most of our daily life, even in meditation retreats, there's always the next thing. 'I'm going to meditate for an hour and then get up, and then it's the next thing.' ... In the dark, there's no next thing."

As a physician who works with hospice patients, Biddle says his time in darkness allowed him to address and release trauma he'd been holding onto and come back to his job feeling renewed.

"My job, it is hard, and there's suffering all day long," he says. "At least for now, I'm able to both be more present in my body and be more available for the people I'm working with."

How to know if a darkness retreat is right for you

Darkness retreats are difficult and not for everyone.

Berman says it's essential to make sure participants feel safe throughout the experience, which can include confronting difficult parts of yourself. According to Sky Cave Retreats' website, participants can ring a bell if they need food or additional attention.

"You open, and you include more of yourself, but that includes including uncomfortable sensations, uncomfortable feelings, difficult emotions, difficult thoughts," he says.

Biddle, who participated in a Sky Cave Retreat, says he felt well-supported on the retreat, noting Berman checked on him every day during it. He also said the door to the cabin remains unlocked so participants can step outside if needed. There's also a light switch in the room that participants can turn on if they choose.

Still, Biddle wouldn't recommend it to people, even close friends, because of how challenging it is. Instead, he thinks only those who are motivated enough to seek out a darkness retreat themselves should consider it.

Berman says it's important to keep in mind how difficult a darkness retreat is when watching videos of people leaving the retreat on social media. Many of these people, he says, experienced deep insight, but many are also just relieved it's over.

More:I spent two hours floating naked in a dark chamber for my mental health. Did it work?

Is a darkness retreat healthy?

Kevin Chapman, a psychologist and the founder and director of The Kentucky Center for Anxiety and Related Disorders, says people will respond to darkness retreats and other forms of sensory deprivation differently. For some, it's a calming experience, but for others it can be quite frightening.

If someone is not used to being alone with their thoughts, doing so might make them feel trapped. Additionally, he says anyone struggling with claustrophobia, agoraphobia or high anxiety might want to steer clear.

Psychotherapist Stephanie Sarkis says there are less intense ways of promoting bliss, euphoria and gratitude than spending days in total darkness, which can trigger people's past trauma.

"Do we really need to go to that extreme to feel that similar sensation?" she says. "I would argue that you can experience that type of feeling grateful for things and having a new aspect of things through meditation, which has research behind it."

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