Friends tell PEOPLE the troubled Johnson & Johnson heiress led an increasingly erratic existence in the months before she was found dead in her Los Angeles home Tuesday. "She had so many ups and downs, but lately, it wasn't very good," a pal tells PEOPLE. "She tried rehab, wanted things to change … but it didn't stick."
The source says Johnson had recently been acting more and more bizarre. "Just a few months ago, she was living like a crazy person," the pal says. "Super erratic behavior. People could barely be around her."
Johnson, an openly gay socialite engaged to Tila Tequila, had a history of diabetes. Her cause of death appears to be natural, according to officials, but toxicology reports are still pending.
"Casey thought being with a woman would make her edgy," another friend tells PEOPLE. "She never had luck with men because she was so weird and awkward."
Strained too were relationships with other friends and family. The friend says she spent a lot of time with Johnson until a year ago – when she stopped talking to her. "She was very troubled. Several of her family members didn't speak to her. The other Johnson kids felt she damaged their name."
Johnson was estranged from her family because of her crazy antics and mishandling of her fortune, friends say. "Her family couldn't handle her behavior and lack of respect, so they cut her off," the pal says. "They thought it would teach her to turn things around."
But, her estranged friend tells PEOPLE: "Casey was so screwed up by the end, I don't think she knew anything about anything anymore. She was long gone."
Meanwhile, fellow socialite Brittny Gastineau defends her friend, telling PEOPLE she's in shock. "It's so upsetting and it's so sad. There are no words to describe it. I saw her a month ago. She was totally fine and happy, and it was all cool," she says of a trip to an L.A. nail salon with Johnson and Johnson's ex-girlfriend Courtenay Semel. "She loved getting her nails done."
As for her demeanor, Gastineau says Johnson was "a very sweet person. She was always adorable, and and a very kind person. I've known her for so long, since I was 15. It's just shocking."
Reporting by DAVID CAPLAN, JENNIFER GARCIA and ALYSSA SHELASKY