Ex-wrestling star Chyna died of an accidental overdose of a prescription sleeping pill and a tranquilliser, according to her manager Anthony Anzaldo.
Anzaldo, who discovered the 46-year-old former WWE star dead in her bed at her Redondo Beach home in Los Angeles on April 20, said it was "98% certainty and 2% speculation" she died of an accidental overdose.
He believes she may have died two or three days before she was found.
Chyna, whose birth name was Joan Marie Laurer, was a lifelong insomniac who had prescriptions for Ambien and a generic version of the anti-anxiety drug Valium, Anzaldo said.
Days before she was found dead, Chyna appeared rambling and disjointed as she wandered around her apartment wearing headphones and a feather in her hair in a 13-minute video she posted online.
Chyna had acknowledged struggling with addiction in the past.
Anzaldo said she had been known to binge drink but had not had a drink for several weeks, and there was no alcohol in her home at the time of her death.
He said he suspects that Chyna had been "self-medicating a little bit more than she should have" because she had begun seeing a psychiatrist for the first time, was attending a women's domestic violence group and had visited the grave of her estranged father.
She was trying to deal with issues of abandonment and violence from previous relationships, Anzaldo added.
"A lot was going on in her life emotionally. But she wasn't depressed; it was just a lot to deal with," he said.
"The drugs may have clouded her memory so that she took more than she realised.
"She accidentally, over the course of two or three weeks, misused her legally prescribed medication," he added.
"They're not going to find, like, 60 pills in her stomach."
No cause of death has been released by the Los Angeles County coroner's office because results of toxicology tests are pending.
The death was initially reported as a possible overdose with prescription drugs, "but we don't know", coroner's assistant chief Ed Winter said.