"Everybody spouted the same things and there was a lot of rules, a lot of control. It was really awful."
Her time spent in the cult damaged her ability to form lasting relationships with people, she said.
"Because of the devastation, emotional and psychological of the cult, I have not been successful in my relationships and finding a permanent partner and I am sorry about that," she said.
"I think it is our natural state to be connected like that. I don't think you ever change your trigger points, but at least you can be aware of them and maybe avoid situations that might make you vulnerable, especially in relationships."
"It's astounding that something you went through at such an early stage of your life still has such a potential to be destructive," Close went on.
"I think that's childhood trauma. I am psychologically traumatised."
And she went on to address the mental illness within her family, particularly her sister Jessie Close and her son Calen Pick.
Jessie reached out for help when they were at their family home in Wyoming, the actress shared.
"I remember her kids were already loaded in her car and she came up to me across the driveway and said, 'I need help. I can't stop thinking about killing myself,'" Close recalled.
"For me, it was a shock."
Close eventually took her sister to a psychiatric hospital in Massachusetts, where she was finally diagnosed as bipolar 1 with psychotic tendencies.
"Jessie told me she was afraid that if parents found out that she had bipolar 1 that they wouldn't allow their children to play with her daughter," Close shared.
The Hillbilly Elegy actress cofounded non-profit organisation Bring Change to Mind in 2010, pledging to raise awareness and end the stigma around mental illness.
"You can't solve problems unless you start talking about them - and not whispering," she told People earlier this month.
"That changes everything."
And the actress said she's been inspired by the honesty of her sister and her nephew as they shared their stories.
"That they speak publicly on a national platform about what they actually lived with, that's just raw courage.
"And they have been my heroes, even though that's an overused word, they truly are."
WHERE TO GET HELP:
If you are worried about your or someone else's mental health, the best place to get help is your GP or local mental health provider. However, if you or someone else is in danger or endangering others, call 111.
If you need to talk to someone, the following free helplines operate 24/7:
DEPRESSION HELPLINE: 0800 111 757
LIFELINE: 0800 543 354
NEED TO TALK? Call or text 1737
SAMARITANS: 0800 726 666
YOUTHLINE: 0800 376 633 or text 234
There are lots of places to get support. For others, click here.
